On March 12, a Colorado judge struck down Boulder’s municipal ban on assault-style rifles.

On March 16, a 21-year-old suburban Denver man bought a Ruger AR-556 semiautomatic pistol.

On March 22 he allegedly shot 10 people at a Boulder supermarket, killing all including a police officer.

The assault-style ban set by the municipality fell after a two-year court case, but it is sure to stoke battles nationwide over municipal attempts to pass firearms regulations that are stricter than state or federal laws.

The Boulder Police Department has not said where the suspect purchased the Ruger AR-556 pistol. Nevertheless, the pistol — which is designed to operate like a rifle — would have been outlawed under the city’s ban.

Over the last few decades dozens of other towns, villages, and cities have found themselves defending their efforts to restrict firearm sales and possession and use inside their communities.

They’re up against a campaign of nearly identical state laws, known as model legislation, by the National Rifle Association and other groups to mandate “preemption” — meaning local law can’t trump state or federal rules.

Preemption creates tension among conservatives, who traditionally favor local control and limited government, but when it relates to gun rights advocate for uniformity in lieu of a chaotic patchwork of laws. States have used similar arguments to overrule local bans on soda, plastic bags, and short-term vacation rentals. 

Groups like the Second Amendment Foundation are on constant alert for new attempts to pass restrictions and have sent a wave of hundreds of warning letters to municipalities as a precursor to lawsuits. Last year, the group joined 21 civil suits in several states.

USA TODAY and The Trace analyzed preemption laws in the wake of the deadly supermarket massacre on March 22.

More than 40 states have passed broad firearm preemption laws to block locally tailored legislation. Only Connecticut, Hawaii, Massachusetts, New Jersey, and New York generally allow local officials to pass their own firearms-related public safety laws. California and Nebraska have narrow preemption laws, which allow regulation in some gun policy areas, but not others. Even then, new laws are routinely challenged in court.

The NRA supported the Boulder preemption challenge, brought by local gun-rights groups, and cheered the judge’s ruling just days before the shooting as “something to celebrate.” Boulder County District Court Judge Andrew Hartman warned in his order that the city’s ban on weapons and large-capacity magazines could lead to “a statewide de facto ban or patchwork of municipalities regulating assault weapons and (large-capacity magazines).”

In addition to the Boulder case, the Second Amendment Foundation and the NRA mostly recently won a February court ruling in Washington State over the city of Edmonds’s “safe storage” law, requiring gun owners to keep their firearms locked up and inaccessible to others, especially children. There, a judge again pointed to the state’s 36-year-old preemption statute.

“Preemption uniformity was a good idea in the 1980s and it is still the most commonsense way to deal with firearms regulation,” Alan Gottlieb, the SAF founder said at the time. “What is the law in one part of a state should be the law in all parts of that state.”

The Second Amendment Foundation and others like it have grown in prominence in recent years as part of the gun rights lobby that includes former NRA members who felt the organization wasn’t doing enough to protect individual gun rights. 

Powerful national gun violence prevention groups backed by former New York Mayor Michael Bloomberg and former U.S. Representative Gabby Giffords like Everytown, Moms Demand Action, and the Giffords Law Center work to fight off those challenges. They funded and partnered with Boulder in its attempts to defend the assault weapons ban, reducing costs to taxpayers, City Attorney Tom Carr said. (Everytown provides grants to The Trace through its nonpolitical arm. Here’s our list of major donors and our policy on editorial independence.)

Hannah Shearer, Giffords’s litigation director who helped on the Boulder lawsuit, said the intent of the 2018 law was to prevent access to “weapons that we know fuel deadly gun rampages.”

“Boulder and all communities should have the right to adopt the local gun laws that best protect their own residents from violence,” Shearer said.

Ben Geffen, a staff attorney with Philadelphia’s Public Interest Law Center, which is representing gun violence prevention groups aiding that city’s efforts to uphold a gun-related ordinance, said preemption laws stop municipalities from tailoring regulations to the needs of their communities. 

After the shooting deaths of 17 people at Marjory Stoneman Douglas High School in Parkland, Florida, sparked national outrage, the Boulder City Council approved banning assault-style rifles and reducing the allowed capacity of ammunition magazines. The ordinance drew an immediate legal challenge, and the district court judge who ruled on March 12 said that Boulder had overstepped its bounds, citing a 2003 Colorado law restricting municipal power over firearm regulation. 

“What we saw in Boulder is another example of how a municipality was frustrated in its ability to regulate firearms when the state failed to do so,” Geffen said. “There’s no way to know if Boulder’s enforcement of those regulations would have stopped the shooting we saw yesterday, but there’s ample literature to show that, even when gun safety measures are implemented in only one part of the state, they do put a meaningful dent in the gun violence problem.”

History of preemption

Gun policy groups point back to the colonial era, when Philadelphia and Boston passed gunpowder and gun use laws, as evidence that state legislators expressly granted cities the power to enact local rules about firearms. They also say that violent frontier towns like Dodge City and Tombstone needed to have the flexibility to make visitors drop off revolvers with the sheriff at the city limits.

The spark that created the decades-long state legislative battle to block a municipal patchwork of firearm laws started more recently in Morton Grove, Illinois, when the village adopted a local ordinance prohibiting the possession of handguns. 

The NRA’s reaction was swift. In 1981, it backed a state law to block other laws statewide, a model that would be replicated in more than three dozen other states. 

Some state versions of preemption statutes include penalties for lawmakers: In Florida, local officials face a $5,000 fine if they defend rules stricter than the state’s; Nevada awards attorneys fees to anyone who successfully challenges a local firearms law; Kentucky politicians face criminal penalties and civil damages if they violate the state’s firearm preemption law. 

In 2014, Pennsylvania Governor Tom Corbett approved a bill making it easier for outside groups to sue cities and towns for enacting their own gun restrictions. A state court eventually struck down that legislation on a technicality. By then, more than 100 municipalities had opted to repeal their ordinances rather than risk facing costly lawsuits. 

The preemption statute remains on the books in Pennsylvania, where plaintiffs have continued to cite it in seeking to overturn gun laws by the state’s major cities. An Allegheny County judge in 2019 struck down three gun-control measures passed by Pittsburgh following the fatal shootings of 11 people at the Tree of Life Synagogue. And Philadelphia is currently embroiled in a lawsuit over its enforcement of a local requirement that gun owners notify authorities when their weapons are lost or stolen. 

Philadelphia Councilmember Kenyatta Johnson, who chairs the city’s Special Committee on Gun Violence Prevention, said the Boulder shooting exemplified the “critical importance” of giving municipal leaders the power to enact policies that keep guns out of the hands out of dangerous people. 

“Preemption has tied our hands behind our backs as we fight against this senseless gun violence taking place in our communities,” Johnson said. “In Philadelphia, we nearly lost 500 people to homicides in 2020, and we’re on pace to pass the 500-mark in 2021 if we do not get this violence under control.”

What’s next for preemption, gun laws

A previously scheduled U.S. Senate hearing on March 23 took on renewed vigor as legislators debated two measures to expand background checks and close the so-called Charleston loophole — a gap in federal law that lets gun sales proceed if a background check is not completed within three business days.

President Biden on Tuesday urged Congress to pass the bills and also called for renewal of the federal assault weapons ban that expired in 2004.

Legal threats will continue for communities looking to take action on gun policy while Congress remains deadlocked, largely due to the filibuster and requirement that the Senate get 60 votes for federal action.

Not all city officials will respond to or engage with those threats. In 2013, when the Second Amendment Foundation sent a raft of 28 legal threat letters to Maryland town officials, then-Walkersville Town Commissioner Russell Winch said he simply ignored it.

“We were confident that our town code was within our rights under state law,” Winch said. “Sometimes, you have to stand your ground and make the best decisions for the town.”

The town maintains its ban on carrying loaded firearms within town limits, although with a list of exemptions including for those with state handgun permits. 

That type of patchwork of laws is exactly what gun rights activists fear most, said Aidan Johnston, the director of federal affairs at Gun Owners of America.

He takes an absolutist view of the Second Amendment and pointed to wasteful spending by cities that routinely pass new laws only to have them knocked down by state and federal judges.

“All gun control is unconstitutional,” Johnston said Tuesday. “The Second Amendment is clear that the right shall not be infringed, therefore local and state governments don’t have the authority to put restrictions on possessing or transporting or carrying firearms.”

Eileen McCarron, the president of Colorado Ceasefire Legislative Action, said her group had long considered repeal of the state’s preemption statute one of its highest priorities. In the wake of the March 22 shooting, she said the group is renewing its call for legislators to pass such a bill. 

“We had been talking about seeking a repeal next year… but we believe now is the time,” McCarron said. “It’s just so sad that it takes a tragedy for anything to happen legislatively.”