In the aftermath of the lethal mass taking pictures at a highschool in Parkland, Fla., in 2018, cities throughout the nation started passing their very own gun management legal guidelines when state and federal governments did not act.

The metropolis of Boulder, Colo., was one in every of them, unanimously adopting a wide-ranging ban on the sale and possession of assault weapons, high-capacity magazines and bump-stock units. “I think it’s time to say ‘enough,’” Jill Adler Grano, the City Council member who proposed the ban, said after the council’s initial vote.

Gun rights supporters filed a direct problem, arguing that solely the state might regulate firearms in Colorado, and earlier this month, a state decide agreed. Boulder was prohibited from imposing its almost three-year-old assault weapons ban.

Less than two weeks later a man armed with an assault-style weapon walked into a Boulder grocery store and opened fireplace, killing 10 folks.

The gunman might have bought his weapon in one other city, however there was a notably eager sense of dismay and frustration in a metropolis that attempted, and failed, to forestall one of the horrific sorts of gun violence.

“My heart is broken,” mentioned Ms. Adler Grano, who’s not on the City Council. “We tried so hard to prevent this from happening, yet here we are.”

In the wake of the Parkland bloodbath, Boulder was primed to take motion. The metropolis is just 30 miles away from Columbine High School, the place 12 college students and a trainer had been fatally gunned down in 1999. It is 35 miles from Aurora, the place 12 folks had been killed by a gunman who walked into a movie show and opened fireplace. In all, since 1993, 47 folks have died in mass shootings in public areas in Colorado.

But Boulder’s aborted effort to regulate the sort of weapons utilized in such assaults has illustrated the daunting problem of cities that attempt to go it on their very own: Aggressive authorized challenges have efficiently undermined some native ordinances. Lawmakers who endorse gun management laws have been ousted. The trade retains innovating round gun laws. And maybe most daunting of all is the state legislation that offered the premise for the problem to Boulder’s ordinance, a pre-emption — just like these in impact in additional than 40 states — that offers the state sole authority to manage firearms.

“It’s incredibly challenging,” mentioned Stephen Fenberg, a Democrat who’s Colorado’s Senate majority chief. “We are a traditional libertarian Western state. We’re also a state that has seen a lot of gun violence. It’s a complicated topic for us.”

Across the nation, gun regulation has turn into a patchwork of legal guidelines, with a number of federal, state and native legal guidelines regulating gross sales, storage and allowable specs for firearms.

Gun rights advocates have been sturdy supporters of state pre-emption legal guidelines like Colorado’s, arguing that native ordinances like Boulder’s are a nightmare for gun homeowners who should navigate various restrictions from metropolis to metropolis.

In Colorado, with a sturdy looking custom amongst liberals and conservatives alike, a number of gun management measures have been adopted however there’s additionally highly effective bipartisan assist for Second Amendment rights. Still, a lot of the laws handed have cleared the legislature over the overwhelming opposition of Republican lawmakers.

After the grocery store assault this week, the Colorado State Shooting Association, which is affiliated with the National Rifle Association, mentioned in a assertion that it will oppose all gun management measures as a “mistaken way to attempt to prevent these shootings.”

Taylor Rhodes, the chief director of the gun rights group Rocky Mountain Gun Owners, mentioned lawmakers in Colorado ought to embrace laws that permit the carrying of weapons with out a allow with a view to forestall extra mass shootings. But he acknowledged that gun management efforts have been more and more profitable within the state.

“They’ve been gaining traction over the years, but we’re still here fighting, and we won’t stop fighting,” Mr. Rhodes mentioned.

The state’s regulation historical past has been a sequence of steps, a lot of them halting.

After the Columbine bloodbath, lawmakers proposed to shut a loophole that had allowed folks to purchase weapons at gun exhibits with out a background examine. But it took a voter initiative to make it into legislation.

After the Aurora assault, whose ferocity was accelerated by using a 100-round drum journal, Colorado lawmakers restricted the scale of high-capacity magazines, one in every of a sequence of latest management measures.

Not lengthy after, two Democratic lawmakers who had offered essential assist for the bundle had been pushed out of office in a recall vote.

Ahmad Al Aliwi Alissa, who lived within the close by suburb of Arvada, has been charged with 10 counts of first-degree homicide within the newest assault at a King Soopers grocery retailer in Boulder. Despite Mr. Alissa’s personal history of aggression, he had managed to buy a semiautomatic pistol the week earlier than the taking pictures, and in addition had a second gun in his possession on the time of the assault, in keeping with a police affidavit.

AR-style weapons, first developed for battlefield use, have for years been a rising goal of gun management advocates as such firearms repeatedly are deployed throughout mass shootings.

The gun bought by Mr. Alissa was a Ruger AR-556 semiautomatic weapon, primarily a shortened model of an AR-15-style rifle marketed as a pistol. The authorities haven’t mentioned the place Mr. Alissa purchased the weapon.

Under federal legislation, shortened rifles have strict laws, primarily based on fears that such high-powered weapons will be hid earlier than the fee of crimes. Under Colorado state legislation, such rifles are banned.

But the gun bought by Mr. Alissa, whereas carrying a number of the hallmarks of a longer AR-15, had as a substitute been marketed as a pistol — a gun that may be shot with one hand however which comes with a stabilizer that appears just like the buttstock of a rifle. As such, it will have been allowed below state legislation, nevertheless it seems to battle with Boulder’s assault weapons ban, which prohibits pistols with magazines exterior the grip and in addition units that permit it to be stabilized with each arms.

Guns bought from licensed sellers should undergo a federal background examine, and states have embraced broader background-check guidelines to forestall gross sales to distressed folks exterior of gun shops. States, together with Colorado in 2019, have additionally adopted red-flag legal guidelines that permit a decide to quickly prohibit a particular person’s entry to firearms if they’re discovered to be a hazard to themselves or others.

Mr. Alissa had been convicted of a misdemeanor within the assault of one other pupil in his highschool a few years in the past. And Mr. Alissa’s brother informed CNN that his brother had proven indicators of being paranoid and delinquent. But whereas federal and state legal guidelines can forestall people who find themselves a hazard to the group from buying or possessing weapons, it doesn’t seem that Mr. Alissa’s previous actions ever triggered such restrictions towards him.

In some methods, with neighboring communities carrying extensively totally different gun laws, native ordinances such because the one Boulder handed are statements of political conviction as a lot as they’re efficient prohibitions on weapons.

When Ms. Adler Grano proposed her assault weapons ban, she mentioned she knew the concept had assist from many locals, and felt, after watching a continued political stalemate on the federal degree, that native officers must step up.

“Our country has gone through mass shooting after mass shooting for decades now,” she mentioned. “I have a son in high school, and it just felt like, ‘We have got to do something. If the federal government is not going to take action, we’re just going to keep talking around in circles.”

But the general public’s assist was hardly unanimous. Large numbers of opponents, a few of them armed, spoke up towards the measure at council conferences.

The new legislation elevated the authorized age for shopping for a firearm from 18 to 21 in Boulder, banned the sale of assault-style weapons that met sure standards, required the registration or give up of assault weapons that had beforehand been bought, and decreased the journal capability from the state’s restrict of 15 to 10.

But the brand new laws might solely go thus far. An individual wishing to purchase an assault rifle would solely want to go away metropolis limits to legally buy one, highlighting the constraints of a patchwork, city-by-city strategy to gun coverage.

Rachel Friend, a member of the City Council who previously led the native chapter of Moms Demand Action, a corporation that advocates for gun regulation, mentioned metropolis officers had been satisfied that gun regulation within the nation must come from the underside up — however the decide’s determination overturning Boulder’s ban now threatens their metropolis’s effort.

“I can’t tell you how angering that is,” Ms. Friend mentioned. “I’m supporting and advocating for us to appeal.”