— which would apply the new restrictions to the gun used in the Boulder attack — passed the House 36-28 on Monday. The bill’s Senate sponsors next will move to accept changes made in the House and then send the bill to Gov. Jared Polis.

The governor is expected to sign the measure. At Polis’ behest, lawmakers agreed to weaken the bill’s initial intent of fully banning the sale or purchase of the targeted weapons, unless they were altered to have a fixed magazine — meaning that they could not be reloaded as rapidly.

Still, the measure represents the strongest gun-control legislation passed by Colorado lawmakers since they began undertaking firearm regulation in earnest more than a decade ago.

The bill, which would take effect Aug. 1, 2026, broadly would prohibit the sale, purchase or transfer of gas-operated, semiautomatic firearms that accept detachable magazines — a definition that captures most firearms colloquially known as assault weapons.

Under the bill, the guns could still be purchased by people who’ve passed a background check and completed a training course. The legislation does not ban the possession of any weapon, and it would not apply to common pistols and shotguns. It also exempts , some of which are used for hunting.

The restrictions would apply to the gas-operated pistol used by the King Soopers shooter in March 2021. It would also cover the weapons used in the December 2021 Lakewood and Denver shooting spree; the 2012 Aurora movie theater shooting; and some of those used in the 1999 Columbine High School shooting.

The bill’s sponsors — Democratic Reps. Andy Boesenecker and Meg Froelich — said the bill regulates weapons with a “unique lethality” that have been used in mass shootings across Colorado and the United States.

“A generation after Columbine — (a time) of active shooter drills, of lived experience of mass shootings — you bet I have emotions,” Froelich, an Englewood legislator in her final term, said before the vote Monday. “I’m heartbroken. I’m also determined.”

“The core root of the issue”

Republicans uniformly opposed the bill in the House and the Senate. On Monday, House Republicans questioned the measure’s constitutionality and its usefulness, and they said the law wouldn’t be followed by the people most likely to commit violent crimes.

“Deal with violence,” said Rep. Anthony Hartsook, a Parker Republican. “… The tool that is used is an extension of that violence. Until you address the crimes and the people and the mental health that’s dealing with (violence), you’re not going to get to the core root of the issue.”

SB-3 is the product of months — and, in some ways, years — of debate, negotiation and broader political shifts, all against a backdrop of seemingly ceaseless mass shootings. After two years of failed attempts to pass assault weapons bans, lawmakers introduced the measure in early January with a different approach: banning the sale of many guns that accept detachable magazines.

It’s sponsored by Sen. Tom Sullivan, a Centennial Democrat whose son, Alex, died in the Aurora theater shooting. Sullivan had at more explicit assault weapons bans, but he provided pivotal support for SB-3. He cast it as a way to ratchet up enforcement of the state’s high-capacity magazine ban — which lawmakers passed after the theater shooting.

When the bill was introduced, it had enough House and Senate co-sponsors to clear both chambers. But Polis sought a loophole, a desire enabled by a group of holdout Senate Democrats and the absence of a would-be supporter, then-Sen. Sonya Jaquez Lewis, for the vote.

After acceding to the training and background check changes, Sullivan and co-sponsor Sen. Julie Gonzales shepherded the bill out of the Senate. It was then heavily amended in the House, largely to cut costs in a tight budget year.

Once the Senate’s sponsors accept the House’s changes, the bill goes to Polis. Earlier this month, Polis said he was “confident the improvements made to the bill will … protect our Second Amendment rights here in Colorado and improve the education and gun-safety knowledge of gun owners.”

Significant new gun regulation

Should Polis sign it, SB-3 would be a cornerstone of Colorado’s growing foundation of gun control legislation, and its passage shows just how far the state has moved in the last decade.

In 2013, Democratic lawmakers passed a package of gun-control bills, including the magazine ban. That prompted a successful campaign to recall two Democratic legislators, which then chilled additional gun legislation.

That attitude has changed as voters have increasingly sent Democrats to the statehouse. Those Democrats have grown more comfortable pursuing firearm regulation in a state plagued by mass shootings.

In the past several years, the state has adopted age limits, waiting periods, storage requirements, state permitting for gun sales, and a red-flag law allowing for the temporary removal of a person’s firearms.

Still, SB-3 prompted extensive and heated debate in both chambers, including for several hours before the final vote Monday.

The state’s history of mass shootings was also omnipresent: In response to Republican criticism that the bill would limit “law-abiding citizens” from purchasing firearms, Denver Democratic Rep. Jennifer Bacon read the names of people killed in schools and grocery stores.

Each of them, she said, was a law-abiding citizen who “died of the crime of mass shooting.”

“I want us to recognize,” she said, “that we can prevent the crime of mass murder by gun.”

passed the state Senate last month after coming in for some heavy amendments that would allow otherwise-banned guns to be sold to people who complete training and a background check. The measure is set for a first committee vote in the House on Tuesday before it moves to the full chamber.

Though Republicans have promised to fight the bill and gun-rights groups have pledged to sue, should it pass, the proposal has sufficient Democratic support to clear the legislature and head to Gov. Jared Polis.

Polis, a Democrat, was leery of the stronger version of the bill but is now expected to sign it, said Rep. Andrew Boesenecker, a Fort Collins Democrat and one of the bill’s sponsors. The measure would be the most sweeping gun-control law adopted in the state, even amid Democrats’ many recent efforts to tighten firearm regulations in Colorado.

Here’s a closer look at the bill — and the debate around it.

What exactly would the bill do?

Now that’s it been amended, SB-3 would generally limit the sale of certain semiautomatic firearms that accept detachable magazines and are gas-operated. That applies to the group of guns that are colloquially known as “assault weapons,” such as the AR-15 rifle.

There are loopholes. At the behest of Polis and some moderate Senate Democrats, the bill was amended so it would still allow people to purchase the otherwise-banned firearms under certain conditions. If buyers had previously passed a hunter’s education course, they would need to take a four-hour training session. If they hadn’t, they’d need a 12-hour course.

They would then need to be fingerprinted and background-checked by their county sheriff in a process that’s identical to . That process includes ensuring a person doesn’t have a substance-use disorder and isn’t the subject of a protection order, among other things. The sheriff can also determine if people are a danger to themselves or others; if they are, the sheriff can withhold approval cards.

The measure would ban firearm components that make semiautomatic weapons fire faster. That includes bump stocks, which were briefly banned federally after they were used in the 2017 , America’s deadliest mass shooting. The sale of those components would be banned flat out, regardless of a person’s training or vetting.

Where does Polis stand?

Asked by The Denver Post if the governor now supported the bill, a Polis spokesman said the governor “appreciates” that lawmakers worked with his office on amendments to address gun violence and uphold “our freedom and Colorado’s rich hunting and sport shooting culture.”

Would the bill outlaw possession or require people to turn over their guns?

No. The bill applies only to the sale, purchase, transfer and manufacture of the weapons. It would not be illegal to possess any of the banned firearms, and anyone who owns them now — or before the law would go into effect on Sept. 1 — would be able to keep them without any additional training required.

Gun stores have warned that the proposal would harm their businesses, given the popularity of the AR-15 and other covered guns, though the exemptions would still allow them to be sold to approved customers.

Which guns are covered?

The bill applies mostly to gas-operated, semiautomatic weapons that accept detachable magazines. That essentially covers most — if not all — of the so-called assault weapons common in mass shootings, like the AR-15 and similar guns, two experts told The Post.

Those weapons work by recycling the gas created when the bullet is fired to then cycle the gun and ready it to fire again. They also generally take detachable magazines — which can be rapidly swapped out and, in the case of high-capacity magazines, have been banned in the state for more than a decade.

Another amendment added in the Senate , some of which are used for hunting. Those include some guns that are old enough to have seen action in World War II. But it also includes weapons that are substantially similar to the AR-15, said Aaron Brudenell, a forensic science consultant and firearms expert who conducts trainings for .

Broadly speaking, the bill wouldn’t apply to common handguns, revolvers or shotguns. Most common semiautomatic pistols — like Glocks — are operated by their own recoil, not recycled gas, and thus wouldn’t be covered.

But the bill sponsors are also seeking to curtail pistol variants of the AR-15, the measure would cover some handguns, like . Those handguns use the same operating system as AR-variant pistols, like the one used by the shooter at the Boulder King Soopers in 2021, and would thus be caught in the crossfire of the bill’s efforts to block those weapons.

Brudenell questioned whether the bill could be stretched to cover other common handguns, though the bill’s sponsors and advocates have been adamant it would not.

Boesenecker acknowledged that “a relatively small portion of the (handgun) market” would be covered by the bill, but he said those guns have available alternatives that wouldn’t be affected.

So, then, is this a ban?

That’s a tricky question. The bill was initially described by its sponsors as a way to enforce the state’s 2013 high-capacity magazine ban. But now that the bill would still allow weapons that accept those components to be sold, that argument has lost some ground.

It’s also not quite a ban, since Coloradans could buy AR-15s under the law so long as they passed a training requirement and background vetting.

But such an argument won’t assuage gun-rights groups, which argue that their ability to purchase firearms shouldn’t be infringed at all.

And the loopholes have led to some teeth gritting from the bill’s supporters: After the measure was weakened in the Senate, the advocacy group said it “strongly preferred” the first version but was still happy with the bill’s present state.

How would Colorado’s law stack up?

A number of states have enacted bans on so-called assault weapons, and others have adopted vetting and training requirements before a person can purchase specific weapons, said Alison Shih, senior counsel for , which is backing the bill.

“Many other states have some kind of permit-to-purchase (requirement) for firearms, and many of them have them for all firearms,” she said. “… A third of the U.S. population lives in a state that outright bans a subset of military-style firearms.”

SB-3 is unique in that it would limit the sale of those controversial firearms unless a person is trained and vetted, said Andrew Willinger, the executive director of the at Duke University School of Law.

It’s also unique in that it focuses on certain components — like gas operation and detachable magazines, he said. Other states ban a list of specific weapons, and past unsuccessful bills in the Colorado legislature took that approach.

Is any of this constitutional?

Should this bill reach Polis’ desk and be signed into law, it would almost certainly be challenged immediately in court.

Willinger said the bill was likely on solid constitutional footing, even in a judicial system topped by a conservative U.S. Supreme Court that’s taken a more expansive view of the Second Amendment. The high court turned away to other gun control bills — including a weapons ban and a permitting requirement — and lower courts have upheld the laws in other states, Willinger and Shih said.

Still, Shih and Willinger said they expected the Supreme Court to take up an assault weapons case at some point.

Willinger said the training and vetting requirements added in the Colorado Senate likely put the bill on even firmer ground under the Supreme Court’s , which further expanded gun rights. (Shih said Everytown was confident the original bill would’ve been upheld, too.)

“I suspect the court will take a case like that at some point, but I think the analysis is really quite different when you think about the one Colorado is considering,” Willinger said. “You then basically have an argument that the state can make — that this is just akin to the type of objective licensing approach that states use for conceal-carry, for example. The only thing you have to do is just comply with the series of objective requirements, taking these classes and so on.”

The court����ap conservative majority said Friday that then-President Donald Trump’s administration overstepped its authority with , which allows semiautomatic weapons to fire like machine guns.

Here’s what to know about the case:

What are bump stocks?

Bump stocks are accessories that replace a rifle’s stock, the part that gets pressed against the shooter’s shoulder. When a person fires a semiautomatic weapon fitted with a bump stock, it uses the gun’s recoil energy to rapidly and repeatedly bump the trigger against the shooter’s finger.

That allows the weapon to fire dozens of bullets in a matter of seconds.

Bump stocks were invented in the early 2000s after the expiration of a 1994 ban targeting assault weapons. The federal government approved the sale of bump stocks in 2010 after the Bureau of Alcohol, Tobacco, Firearms and Explosives concluded that guns equipped with the devices should not be considered illegal machine guns under federal law.

According to court documents, more than 520,000 bump stocks were in circulation by the time the government reversed course and imposed a ban that took effect in 2019.

Why were bump stocks banned?

More than 22,000 people were attending a country music festival in Las Vegas on Oct. 1, 2017, when a man opened fire on the crowd from the window of his high-rise hotel room. He fired more than 1,000 rounds in the crowd in 11 minutes, leaving 60 people dead and injuring hundreds more.

Authorities found an arsenal of 23 assault-style rifles in the shooter’s hotel room, including 14 weapons fitted with bump stocks.

In the aftermath of the shooting, the ATF reconsidered whether bump stocks could be sold and owned legally. With support from Trump, a Republican, the agency in 2018 ordered a ban on the devices, arguing they turned rifles into illegal machine guns.

Bump stock owners were given until March 2019 to surrender or destroy them.

What did the justices say?

The 6-3 written by Justice Clarence Thomas said the ATF did not have the authority to issue the regulation banning bump stocks. The justices said a bump stock is not an illegal machine gun because it doesn’t make the weapon fire more than one shot with a single pull of the trigger.

Justice Samuel Alito, who joined the majority, wrote in a separate opinion that the Las Vegas shooting strengthened the case for changing the law to outlaw bump stocks like machine guns. But that has to happen through action by Congress, not through regulation, he wrote.

The court����ap three liberal justices opposed the ruling. Justice Sonia Sotomayor wrote in her dissent that there’s no common sense difference between a machine gun and a semiautomatic firearm with a bump stock.

“When I see a bird that walks like a duck, swims like a duck, and quacks like a duck, I call that bird a duck,” she wrote.

Do any states have their own bans?

At least 15 states and the District of Columbia have their own bans on bump stocks, though some could be affected by the high court����ap ruling.

Most state laws, however, remain in place because the decision covered the ATF rule, not the constitutionality of state-level bans, according David Pucino, legal director of the gun control think tank Giffords.

Who challenged the ban?

A group called the New Civil Liberties Alliance sued to challenge the bump stock ban on behalf of Michael Cargill, a Texas gun shop owner. Cargill bought two bump stocks in 2018 and then surrendered them once the federal ban took effect, according to court documents.

The case didn’t directly address the Second Amendment rights of gun owners. Instead, Cargill’s attorneys argued that the ATF overstepped its authority by banning bump stocks. Mark Chenoweth, president of the New Civil Liberties Alliance, said his group wouldn’t have sued if Congress had banned them by law.

How did the case end up before the Supreme Court?

The Supreme Court took up the case after lower federal courts delivered conflicting rulings on whether the ATF could ban bump stocks.

The ban survived challenges before the Cincinnati-based 6th U.S. Circuit Court of Appeals, the Denver-based 10th Circuit, and the federal circuit court in Washington.

But the 5th U.S. Circuit Court of Appeals based in New Orleans when it ruled in the Texas case last year. The court����ap majority in the 13-3 decision found that “a plain reading of the statutory language” showed that weapons fitted with bump stocks could not be regulated as machine guns.

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The amount of the settlement with MGM Resorts International depends on the number of plaintiffs who take part, according to a statement from Las Vegas law firm Eglet Adams, which represents nearly 2,500 victims and made the announcement just days after the second anniversary of the massacre.

Hundreds of lawsuits have been filed against the owner of the Mandalay Bay resort where the gunman opened fire into an outdoor concert on Oct. 1, 2017. The casino giant also owns the venue where 58 people died and hundreds were injured.

“Our goal has always been to resolve these matters so our community and the victims and their families can move forward in the healing process,” said Jim Murren, chairman and CEO of MGM Resorts. “This agreement with the plaintiffs’ counsel is a major step, and one that we hoped for a long time would be possible.”

An independent administrator will be appointed by a court to dole out money from the settlement fund, attorneys and MGM said. They expect to wrap up the process by late next year.

MGM’s insurers will fund a minimum of $735 million. Depending on the number of victims who participate, the company will contribute more, up to $800 million, according to the victims’ attorneys.

“Today’s agreement marks a milestone in the recovery process for the victims of the horrifying events of 1 October,” Robert Eglet, a lead plaintiffs’ counsel, said in the statement. “While nothing will be able to bring back the lives lost or undo the horrors so many suffered on that day, this settlement will provide fair compensation for thousands of victims and their families.”

He said the deal “represents good corporate citizenship” by MGM Resorts.

The statement comes as another attorney for victims planned a news conference on “extremely important developments” Thursday in San Diego.

Virginia Tech, Virginia, 2007: 32 killed

Sandy Hook Elementary School, Connecticut, 2012: 26 killed

Umpqua Community College, Oregon, 2015: nine killed

Marjory Stoneman Douglas High School, Florida, 2018: 17 killed

Santa Fe High School, Texas, 2018: 10 killed

More than 200 lives have been claimed in American school shootings since the massacre at Columbine High School 20 years ago this week. That total doesn’t include hundreds more murdered in mass killings in nonschool settings, such as the 2017 Las Vegas shooting (58 killed) or the Pulse nightclub massacre in Orlando, Fla., the year before (49 killed).

Yet the ability to contain the loss of life from these tragedies remains stalled, as Second Amendment defenders and gun control advocates continue their faceoff in what has become an ossified and depressingly familiar impasse over gun violence in this country.

“We see the exact same discussion every time a mass shooting happens,” said Jaclyn Schildkraut, an associate professor of criminal justice at the State University of New York in Oswego and an expert on mass shootings. “It’s talked about as control or as rights — it’s viewed as all or nothing.”

As a result, she said, little in the way of federal gun control legislation has passed since two students at Columbine shot and killed 12 fellow students and a teacher at the Jefferson County high school on April 20, 1999.

“If anything, federal regulations have gotten more lax,” Schildkraut said.

At the state level, the response has been more robust and varied across the country since Columbine, with legislation generally following the prevailing political allegiances of the state in which it is passed.

While 14 states, including Colorado, have passed “red-flag laws” — which allow the temporary removal of firearms from a person who has been deemed dangerous to themselves or others — other states are going the opposite way and expanding or strengthening concealed carry laws.

Adam Winkler, a constitutional law professor at UCLA, said the gun issue largely breaks along Republican vs. Democrat and urban vs. rural schisms.

“No issue makes clear the difference between red states and blue states like guns,” Winkler said.

Tom Mauser has been fighting for gun control legislation since his son Daniel was killed at Columbine. As a spokesman for Colorado Ceasefire, a gun control group that formed shortly after the shooting, he sees up close the passion guns and gun ownership engender. Even though his group doesn’t call for disarming Americans, he said gun rights groups often echo that refrain when rallying against legislation.

“We have a gun culture in this country — that’s a cultural thing and it’s not easy to change,” Mauser said, as he sat in the front row of his Littleton church during a recent interview. “They control the narrative. It’s about rights and it’s about confiscation. It’s all about fear.”

But Dave Kopel, an adjunct professor of constitutional law at the University of Denver Sturm College of Law and research director for the libertarian-leaning Independence Institute, said gun control groups have been pouring millions of dollars — led by billionaire former New York City Mayor Michael Bloomberg — into a campaign to paint gun owners as extreme when all they are doing is safeguarding a basic constitutional right.

“There’s no question that anti-gun lobbies had a plan before Parkland, and implemented after Parkland, stigmatizing and demonizing gun owners and Second Amendment supporters in particular,” he said.

Measures struggle

The gun debate continues to play out against the unrelenting and bloody backdrop of gun-related killings in the United States, with the Gun Violence Archive documenting on the order of 12,000 to 15,000 gun deaths annually in this country since 2014.

Last year, 14,720 people died by a bullet in the U.S., according to the group. That figure does not include the more than 20,000 suicides by firearm that occur annually in this country. As these numbers have stayed stubbornly high, so have the passions on both sides of the issue.

That has made for a very uncertain legislative environment for measures designed to ratchet down the level of violence, even as gun rights advocates say those measures do nothing more than infringe on constitutional freedoms.

At the federal level, gun control has been halting at best since Columbine. There was 2007’s NICS Improvement Amendments Act, passed in the wake of the Virginia Tech shooting, that was designed to fortify elements of the National Instant Criminal Background Check System. And last month, the Trump administration’s ban on bump stocks — a device used by the Las Vegas killer to fire at a crowd outside his hotel with machine-gun efficiency — took effect.

But over the last two decades, many proposed gun control measures — even those sponsored by Republicans — have been stymied. One prominent effort repeatedly rebuffed over the years, Schildkraut says in her newly released book “Columbine: 20 Years Later and Beyond,” is a national measure requiring criminal background checks for all guns purchased at gun shows, not just those acquired from licensed dealers.

While Colorado voters overwhelmingly passed a gun-show loophole measure in 2000 after it was revealed that so as to avoid background checks, similar measures at the national level have gone nowhere.

“… Despite numerous attempts to close the gun-show loophole by members of both political parties, one of the most debated perceived causal factors for the Columbine shooting remains unaddressed 20 years later,” Schildkraut wrote.

Meanwhile, there have been a number of federal laws passed that buttress gun rights, including measures in the mid-2000s that required the FBI to destroy the records of approved gun buyers within 24 hours and that shielded gun sellers and manufacturers from lawsuits if their products are used in a crime.

The assault weapons ban signed into law by President Bill Clinton expired in 2004 and has not been renewed.

Guns in the “right hands”

Kopel said gun control proponents are looking at the issue the wrong way. Restricting overall access to firearms through gun control legislation largely hits law-abiding gun owners, he said, as criminals with intent to do harm will find a way to obtain weapons regardless of the law.

He points to the thwarted mass shooting at New Life Church in Colorado Springs in 2007 by a disgruntled 24-year-old Englewood man as a vivid example of why guns in the right hands can be instrumental in halting bloodshed. In that case, a security guard shot the shooter in the foyer of the church, wounding him, before he could move further into the building and claim more lives. Police believe the shooter then turned the gun on himself.

Columbine, Kopel said, changed the way law enforcement approaches an active shooter situation. Officers were heavily criticized after the 1999 massacre for waiting too long before entering the school, allowing the shooters to carry out their deadly plan with almost no resistance.

“I think Colorado and the nation have learned some lessons from Columbine — that guns in the wrong hands are very dangerous to public safety and guns in the right hands protect public safety,” he said.

John Lott, president of the Crime Prevention Research Center and author of “More Guns, Less Crime,” said mass killers often choose a soft target or “gun-free zone” — such as schools — to carry out their attacks. That was true in South Carolina in 2015 when a gunman killed nine members of a black church during a Bible study class and three years earlier when a gunman killed 12 and wounded 70 in a movie theater in Aurora.

It was revealed at trial that the shooter had scouted the Century Aurora 16 theater multiple times and estimated how long a police response would take after he opened fire. According to the killer’s notebooks that police found after the shooting, he had ruled out attacking people at an airport because of “substantial security.”

“It at least shows that he was cognizant of armed security who might have been able to stop him,” Lott said. “These guys might be crazy but they’re not stupid.”

Concealed carry laws, he said, provide a critical level of protection for the public because it “takes away the strategic advantage of the killer.” That is as true in a school as in a movie theater, Lott said.

“If it were me, I would have a sign that would warn that there are select teachers that have concealed handguns to protect the school,” he said. “Make it so that a person, or multiple people, who are unknown to the attacker have a weapon that can stop him.”

President Donald Trump has called for arming teachers, and at least 30 school districts in Colorado, The Denver Post found last year, allow teachers or school staff to arm themselves. But Mauser thinks the idea of arming teachers is a bad one.

“Teachers need to be teachers and not security guards,” he said.

He worries about shooters firing at teachers first, with the assumption they are armed, or police officers targeting armed teachers in the chaos of an active event when it’s not yet clear who the bad guy is. And Mauser questioned how rigorously and how often teachers should be trained in the use of their weapons and where the guns would be safely stored at school.

Finding the line

Since Columbine, the U.S. Supreme Court has handed down two landmark decisions on gun ownership. The first — 2008’s District of Columbia vs. Heller — held that the Second Amendment ensures an individual the right to possess a firearm regardless of whether that person has any affiliation with a militia, striking down Washington, D.C.’s decades-old ban on handgun possession.

Two years later, the court ruled in McDonald vs. City of Chicago that the right to keep and bear arms applies to state law in the same way it does to federal law.

But in Heller, the court said: “Like most rights, the Second Amendment right is not unlimited. It is not a right to keep and carry any weapon whatsoever in any manner whatsoever and for whatever purpose.”

Today, the battle over gun rights and gun control plays out in the nebulous area of what constitutes “in any manner” and “for whatever purpose.”

“Everybody is disagreeing with where the line is,” said Scott Moss, a constitutional law professor at the University of Colorado Law School in Boulder. “Everybody agrees that the right to bear arms doesn’t mean you have the right to arm yourself with a nuclear missile. (Some constitutional rights) are yes, no — some are more of a spectrum.”

For many gun control backers, the prohibition on sheer destructive power should apply to semi-automatic weapons like the popular AR-15, which has been of the past decade. But the powerful National Rifle Association has defended the weapon as and two Democratic lawmakers in Colorado felt the wrath of those opposed to the state’s 15-round magazine limit, passed in 2013, by getting ousted in historic recall elections after voting in favor of the measure.

Experts interviewed for this story don’t see a happy medium on the issue coming any time soon.

“It’s difficult to see Congress compromise on guns when it can’t compromise on anything,” said Winkler, of UCLA. “We’re probably not going to see anything significant at the federal level any time soon.”

In late February, the Democratic-controlled House passed a measure requiring federal background checks for all firearms sales and transfers, but politics watchers say there’s little chance the bill will get through the GOP-led Senate or survive a presidential veto. At the state level, CU Boulder’s Moss said Colorado’s tilt to the left in the last few election cycles doesn’t necessarily track with the public’s view on guns — an issue that tends to create deeply entrenched positions.

“It’s not clear that Colorado’s progressive streak is extending to guns, like it has to LGBT rights,” he said. “I’m not convinced guns are an area where people change their minds a lot.”

The extreme risk protection order — or red flag — bill that was just signed into law got steep pushback in the form of resolutions from several counties, including Weld, Otero and Fremont, in which they declare themselves Second Amendment sanctuary counties where law enforcement is excused from enforcing the new restriction on gun ownership.

But Mauser hasn’t lost hope that sensible measures can move forward. He took heart at the energy and advocacy against gun violence displayed by students in Parkland, following the Valentine’s Day shooting at the South Florida high school last year.

“It has to be the young people taking this on, because my generation has failed,” he said.

Universal background checks and red flag laws may present a level of inconvenience to people trying to lawfully purchase or possess a firearm, but Mauser said that is a reasonable price to pay for maintaining public safety in a country that sees tens of thousands of gun deaths a year.

“Sure, it’s a hassle,” he said. “It’s hassle to bury your kid, too.”

In a 64-page decision, U.S. District Judge Dabney L. Friedrich found that the Firearms Policy Coalition and other groups did not put forth any convincing legal arguments in favor of stopping the Trump administration from carrying out the ban, which targets a device used in the 2017 Las Vegas massacre, the deadliest mass shooting in modern U.S. history.

Friedrich, a 2017 appointee of President Trump to the District of Columbia, ruled it was “reasonable” of the Bureau of Alcohol, Tobacco, Firearms and Explosives to conclude that a bump-stock, which uses the recoil energy from a rifle to automatically fire the next round, performs the same function as a machine gun and should therefore be banned just like machine guns under federal law.

Trump moved to ban bump stocks in the wake of the Las Vegas shooting with loud bipartisan support from Congress and anti-gun-violence advocates. The October 2017 shooting left 58 people dead and hundreds wounded after a man rained gunfire on concertgoers at the Route 91 Harvest Festival, firing from the 32nd floor of his Vegas hotel. Affixed to a dozen of the 23 rifles found in his room were bump stock devices, which allowed him to fire multiple rounds more quickly.

The Firearms Policy Coalition sued the Trump administration in December after ATF changed federal rules to ban the devices at Trump’s request. The group argued that the agency had flouted numerous procedures when it made the rule change, building its case mostly on procedural law rather than invoking the Second Amendment. In part, the group challenged ATF’s divergence from its previous interpretation of the law, when it concluded in the mid-2000s that only a certain type of bump stock should be banned.

But Friedrich said ATF did not violate any laws under the Administrative Procedure Act as it reconsidered whether a bump stock was a machine gun and declined to issue a preliminary injunction against the ban.

“That this decision marked a reversal of ATF’s previous interpretation [of the meaning of bump stock] is not a basis for invalidating the rule,” Friedrich wrote, “because ATF’s current interpretation is lawful and ATF adequately explained the change in interpretation.”

The ruling puts gun-rights groups on a tight timeline should they appeal the ruling, which they indicated in court filings that they plan to do. ATF’s bump-stock ban is slated to go into effect on March 26. At that point, bump-stock owners will be required to destroy the devices by melting or shattering them or to drop them off at an ATF office.

In its rule change, ATF simply clarified the definitions of words like “automatic” and phrases like “single function of the trigger.” The agency has been debating whether certain types of bump stocks should be banned since at least 2002. It decided that a single type of bump stock was illegal in 2006 before expanding that interpretation to all bump stocks in December.

The gun-rights groups also tried to challenge the validity of the rule on the grounds that then-acting attorney general Matthew Whitaker had been unconstitutionally appointed by Trump. Friedrich found that this argument also lacked any merit.

But while support for banning bump stocks is strong on the left, at least some Democrats opposed the ATF rule change. Sen. Dianne Feinstein, D-Calif., argued that the authority to make such changes should rest with Congress.

Feinstein predicted in commentary for The Washington Post that the ban would end up entangled in litigation, possibly preventing it from taking effect.

“Support for banning bump stocks is widespread, and it’s encouraging to see the Trump administration take action on gun safety,” she wrote. “But let’s not celebrate too quickly. Presidents can rescind regulations just as easily as they create them, and in this case, the bump stock ban will likely be tied up in court for years.”

The lawsuit filed by the Firearms Policy Coalition is not the only one pending against the Trump administration over the bump stock ban. A similar case filed by gun-rights groups in the Western District of Michigan is set for a hearing next month.

Its report on the 2017 massacre in Las Vegas was just three pages.

The brevity prompted disbelief and outrage from survivors and relatives of victims. Even President Donald Trump said he was disappointed and surprised, though he said he understood the FBI had not determined a motive in the Vegas shooting.

“I don’t think they did that thorough of an investigation,” said Christine Caria, who survived the attack that killed 58 people and injured nearly 900 others. “It seems like it was really fast.”

Close to 16 months after the shooting, the FBI’s long-awaited report — released Tuesday — did little to shed light on the investigation and left its main question about motive unanswered.

“They were unable to find a real reason, other than that obviously he was sick, and they didn’t know it,” Trump said in an interview with The Daily Caller. “So, I was a little surprised and a lot disappointed that they weren’t able to find the reason, because you’d like to find a reason for that and stop it.”

The report compiled by the FBI’s Behavioral Analysis Unit found that gunman Stephen Paddock sought notoriety in the attack, but it cited no “single or clear motivating factor” to explain why he opened fire from his suite in a high-rise casino hotel on 22,000 people attending an open-air concert.

Aaron Rouse, special agent in charge of the FBI’s Las Vegas office, defended his agency’s handling of the investigation — calling it a “herculean” effort.

More than 1,000 FBI employees worked on the investigation, he said, adding that it would be a “mischaracterization” to deem the FBI’s inability to identify a specific motive as a failure.

“Everything that could be done to figure out why has been done,” Rouse said.

Sandra Breault, FBI spokeswoman in Las Vegas, did not immediately respond Thursday to messages about the president’s comments.

Jack Levin, author of several books on serial killings and professor emeritus of sociology and criminology at Northeastern University in Boston, said he doubted authorities had any reason to withhold information about Paddock.

But he said he would have liked the FBI report to detail whether a catastrophic loss might have triggered Paddock to undertake the attack.

“I’ve studied hundreds of cases, and in almost every case there has been a catastrophic loss,” Levin said. “Loss of a job, loss of lots of money, becoming deeply in debt, losing a relationship or a loved one, separation from important friends, an eviction.”

Mary Ellen O’Toole, who retired as an FBI profiler in 2009, said agents typically compile long reports after extensive analysis to help law enforcement and the public understand the investigation and what can be done to prevent future attacks.

“People really want more information in cases like this,” she said. “They want to know what we missed, who knew something and what was the motivation so this doesn’t happen anymore.”

The FBI said it enlisted experts who spent months examining several factors that might have prompted the rampage.

The report said the gunman was inspired in part by his father’s reputation as a bank robber who was once on the FBI’s most wanted list.

In many ways, Paddock was similar to other shooters the FBI has studied — motivated by a complex merging of developmental issues, stress and interpersonal relationships. Paddock’s physical and mental health had been declining before the shooting. His wealth had diminished, and the 64-year-old struggled with aging, the FBI said.

Trump, who met with victims at a hospital in the days after the massacre, said the FBI “worked very hard on the case” but “they just were unable to find anything.”

“A very sick person, who just, people never saw that coming.” Trump said.

O’Toole now heads the George Mason University forensic science program in Fairfax, Virginia. She said FBI profilers often work like consultants for police departments in major investigations.

She cautioned that while she didn’t know the specific details of the arrangement following the Las Vegas shooting, police may have told the FBI what specific information they wanted agents to investigate and report on.

Las Vegas police have declined to comment on the FBI report. The department closed its investigation in August with the release of a 187-page report — also without identifying a reason for Paddock’s rampage.

In response to a court order in a public records lawsuit, Las Vegas police previously released thousands of pages of police reports, witness statements and hundreds of hours of officer body camera and surveillance video footage.

“People have a hard time understanding motive,” O’Toole said. “They think of money or sex. We’re seeing more and more these motives are personalized like a desire to be infamous or to be internationally known.”

Paddock broke out a window in his 32nd-floor suite at the Mandalay Bay casino-hotel and fired more than 1,000 rounds in 11 minutes into a crowd of music fans below.

He had 23 assault-style weapons, including 14 fitted with rapid-fire “bump stock” devices, which the Trump administration has banned, beginning in March. Authorities said Paddock’s guns had been legally purchased.

Paddock did not leave a manifesto or suicide note, and federal agents believe he had planned to fatally shoot himself after the attack, according to the report.

“Bottom line is he didn’t want people to know” his motive, Rouse said.

Levin said he thinks Paddock wanted most to be remembered.

“People say we don’t know Paddock’s motive,” Levin said. “But I think his motive was to go down in infamy. That’s a motive that’s shared by lots of killers.”

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Ritter reported from Las Vegas. Associated Press writer Michelle L. Price in Las Vegas contributed to this report.

“It wasn’t about MGM, Mandalay Bay or a specific casino or venue,” said Aaron Rouse, the special agent in charge of the FBI’s Las Vegas office. “It was all about doing the maximum amount of damage and him obtaining some form of infamy.”

Rouse says Stephen Paddock acted alone when he planned and carried out the attack. The 64-year-old fatally shot himself after opening fire from his hotel suite.

Rouse says the reason for Paddock’s rampage remains a mystery after months of study by agents and behavioral specialists. Almost 900 people were injured during the Oct. 1, 2017, attack on an outdoor country music concert.

Paddock, 64, was a retired postal service worker, accountant and real estate investor who owned rental properties and homes in Reno and in a retirement community more than an hour’s drive from Las Vegas, held a private pilot’s license and liked to gamble tens of thousands of dollars at a time playing high-stakes video poker.

His bank robber father was once on the FBI Most Wanted list. His younger brother, Eric Paddock, called him the “king of microaggression” — narcissistic, detail-oriented and maybe bored enough with life to plan an attack that would make him famous.

His ex-wife told investigators that he grew up with a single mom in a financially unstable home and he felt a need to be self-reliant.

Police characterized him as a loner with no religious or political affiliations who began stockpiling weapons about a year before the attack, spent more than $1.5 million in the two years before the shooting and distanced himself from his girlfriend and family.

He sent his girlfriend Marilou Danley to visit her family in the Philippines two weeks before the attack and wired her $150,000 while she was there. Danley, a former casino worker in Reno, returned to the U.S. after the shooting and told authorities that Paddock had complained that he was sick and that doctors told him he had a “chemical imbalance” and could not cure him.

Danley, who is Catholic, told investigators that Paddock often told her, “Your God doesn’t love me.”

A Reno car salesman told police that in the months before the shooting Paddock told him he was depressed and had relationship troubles, and his doctor offered him antidepressants but told police that Paddock would only accept a prescription for anxiety medication.

Yet Paddock’s gambling habits made him a sought-after casino patron. Mandalay Bay employees readily let him use a service elevator to take multiple suitcases to the $590-per-night suite he had been provided for free. Authorities said he asked for the room, which had a commanding view of the Strip and the Route 91 Harvest Festival concert grounds across the street.

The night of the massacre, Paddock fired more than 1,000 rounds with assault-style rifles in 11 minutes into the crowd of 22,000 country music fans. Most of the rifles were fitted with rapid-fire “bump stock” devices and high-capacity magazines. Some had bipod braces and scopes. Authorities said Paddock’s guns had been legally purchased.

Las Vegas police closed their investigation last August, and Clark County Sheriff Joe Lombardo declared the police work ended after hundreds of interviews and thousands of hours of investigative work. Lombardo vowed to never again speak Paddock’s name in public.

A separate report made public in August involving the Federal Emergency Management Agency found that communications were snarled during and after the shooting. It said police, fire and medical responders were overwhelmed by 911 calls, false reports of other shootings at Las Vegas casinos, and the number of victims.

Hotel security video and police officer body camera recordings made public under court order in a public records lawsuit by media including AP showed police using explosives to blast through the door of the 32nd-floor hotel suite where Paddock was found dead from a self-inflicted gunshot wound. The Clark County coroner ruled his death a suicide.

Paddock left no note providing an explanation.

The volumes of police materials also including written reports and witness accounts provided glimpses of horror, heroism and heart-wrenching drama. They did not provide a motive for Paddock’s actions.

Some of the top priorities for the industry — expanding the reach of concealed carry permits and easing restrictions on so-called “silencers” — remain in limbo, and prospects for expanding gun rights are nil for the foreseeable future.

Instead, fueled by the deadliest mass shooting in modern U.S. history, the federal government banned bump stocks and newly in-charge U.S. House Democrats introduced legislation that would require background checks for virtually every firearm sale, regardless of whether it’s from a gun dealer or a private sale.

Even without Democrats’ gains in November’s midterm elections, the industry was facing a so-called “Trump slump,” a plummet in sales that happens amid gun rights-friendly administrations. Background checks were at an all-time high in 2016, President Barack Obama’s last full year in office, numbering more than 27.5 million; since then, background checks have been at about 25 million each year.

Gary Ramey, owner of Georgian gunmaker Honor Defense, says the mood at last year’s SHOT Show, which stands for Shooting, Hunting and Outdoor Trade, was subdued. He’s expecting the same this year.

“There was no one to beat up. You didn’t have President Obama to put up in PowerPoint and say ‘He’s the best gun salesman, look what he’s doing to our country,'” he said.

“Numbers are down,” he added. “You can’t deny it.”

Robert J. Spitzer, chairman of political science at the State University of New York at Cortland and a longtime watcher of gun issues, said that not only have shifting politics made it difficult for the gun industry to gain ground but high-profile mass shootings — like the Las Vegas shooting that happened just miles from where the SHOT Show will be held and the Parkland, Florida, high school shooting — also cast a pall.

“After the Parkland shooting, (gun rights’ initiatives) were kind of frozen in their tracks,” Spitzer said. “Now there’s no chance that it’s going anywhere.”

It’s easier to drive up gun sales when there’s the threat or risk of gun-rights being restricted, he said. “It’s harder to rally people when your target is one house of Congress. It just doesn’t have the same galvanizing effect.”

The National Shooting Sports Foundation’s SHOT Show has been held annually for more than four decades. This year more than 60,000 will attend the event that runs Tuesday through Friday — from gun dealers and manufacturers to companies that cater to law enforcement. There’s a wait list for exhibitors that is several hundred names long and it will have some 13 miles of aisles featuring products from more than 1,700 companies.

Last year’s show in Las Vegas was held just months after a gunman killed 58 people and injured hundreds at an outdoor music festival. The massacre was carried out by a gunman armed with bump stocks, which allow the long guns to mimic fully automatic weapons.

Organizers last year restricted media access to trade journalists. This year’s show will again allow reporters from mainstream media to attend.

Gun-control advocates are rejoicing in the gun industry’s misfortunes of late and chalking it up to not just shifting attitudes among Americans but a shift in elected political leaders.

“Without a fake menace in the White House to gin up fears, gun sales have been in a Trump slump and, as a result, the NRA is on the rocks,” said John Feinblatt, president of Everytown for Gun Safety, a group founded by former New York Mayor Michael Bloomberg.

Joe Bartozzi, the new president of the National Shooting Sports Foundation, said the industry isn’t disturbed by the drop in gun sales or the shift in federal politics. While Democrats who ran on gun-control platforms made huge gains in the House, he sees the Senate shifting to the other end of the spectrum.

“Having been in the industry for over 30 years and seeing the trends of gun sales ebb and flow over time, it’s very hard to put your finger on any one specific issue as to why this happens. It’s just the cyclical nature of the business,” he said.

Trump’s campaign was bolstered by about $30 million from the National Rifle Association and when he took office, the industry had hoped that a host of gun rights would be enacted. The Trump administration quickly nixed an Obama-imposed rule that made it more difficult for some disabled people to purchase and possess firearms.

But other industry priorities, such as reciprocity between states for carrying certain concealed firearms and a measure that would ease restrictions on purchasing suppressors that help muffle the sound when a gun is fired, failed to gain traction.

For now, Bartozzi said his organization is focused on a measure that would expand public gun ranges, funded by an existing tax on firearms and ammunition sales that supports conservation, safety programs and shooting ranges on public lands. The hope is that increasing the number of public ranges will encourage more people to become hunters.

“Times have changed,” DeAngelis said.

In a sign of the times, DeAngelis joined Attorney General Cynthia Coffman, Lt. Governor Donna Lynne and a host of community partners Tuesday morning to announce a new non-profit dedicated solely to helping victims of mass tragedy.

The establishes a safe, secure way for the public to send money to support victims and their families after a mass casualty incident in the state. The attorney general’s office has provided $1 million in seed funding.

“This is not something any of us want to think about,” Coffman said, “and we hope we don’t have to use this fund. But we owe it to Coloradoans to be prepared.”

The fund will provide immediate and long-term assistance for victims, families and communities. The seed money will allow the organization to send money the day of or the day after a mass casualty event. The fund could provide medical treatment, food, housing and transportation for family members.

The genesis of the fund started in 2016, Coffman said. But it gained steam after the Las Vegas shooting in October 2017, when Colorado sent personnel to assist in the response. The result is one statewide fund that aims to keep money flowing to victims, not bad actors.

“We know from our experience that people here are very generous,” the attorney general said. “But this also creates the opportunity for scam and fraud.”

Coffman contacted DeAngelis six months ago to see what he thought about the idea.

“It was a no-brainer,” DeAngelis said about getting involved as a board member.

“It would have made a big difference if we had something like this (after Columbine), ” he said. “If something had been in place then, it would have helped the healing.”

Since Columbine, Colorado has seen a host of mass shootings. In December 2007, a 24-year-old man opened fire at two churches — Youth With a Mission in Arvada and New Life Church in Colorado Springs — killing four people and wounding five others. Five years later, 12 were killed and 70 injured in a shooting the Century Aurora 16 Theater. Then there was the 2015 Planned Parenthood shooting in Colorado Springs, when a gunman killed three people, including a police officer.

“I hope — I pray — we don’t have to use this fund,” DeAngelis said. “But odds are we will.”