The bill did pass the Democrat-led House. Only two Republicans voted for it, foreshadowing this week’s claims by senators that the bill didn’t protect gun owners.

Despite the proliferation of similar proposals after a gunman killed 17 people at a Florida high school in February and Colorado’s own history of mass shootings, the short-lived debate showed the battle lines on gun policy in Colorado politics have barely shifted.

Similar “red flag” laws have been introduced in nearly 30 states since the Parkland, Florida killings, with lawmakers in Florida, Maryland and Vermont passing legislation.

The issue simmered in Colorado’s divided Legislature until about a week before the end of the legislative session, when a top Republican in the Democrat-led House and a Democratic colleague unveiled the proposal.

Supporters tried to keep the focus on the 29-year-old peace officer shot to death on New Year’s Eve in suburban Denver, naming the bill after slain Douglas County Sheriff’s Deputy Zackari Parrish.

Public records show the gunman, Matthew Riehl, threatened officials at the Wyoming law school he attended, threatened lawsuits against family members if they kept him from accessing firearms and was placed under a 72-hour mental health hold in 2014 at a Veterans Affairs psychiatric ward.

None of that appears to have disqualified him from buying weapons.

Colorado Republicans claimed a red flag law could discourage gun owners from seeking treatment for mental health problems. They said personal spats could lead to requests for an emergency order without giving the gun-owner an immediate opportunity to respond.

“When it comes to the potential for gun confiscation without proper due process … I do not think it should be any surprise what happens to that bill,” GOP Senate President Kevin Grantham predicted Monday.

Under the proposal, family members or law enforcement could have asked a court to issue a “temporary extreme risk protection order” if they believed someone posed a risk to themselves or others, and require them to hand in all firearms to local law enforcement. Another hearing would be required within 7 days of the initial order, and a judge would decide whether to end or extend an order for 182 days.

The gun owner could ask a judge to reconsider during that 182-day period.

Supporters argued that process ensured that gun owners’ rights were protected but would help prevent suicide or killings. At an April 30 press conference unveiling the bill, Spurlock said it could have saved Parrish’s life.

“What we’re trying to do is save lives,” he said. “And if you get in front of this or you interfere with it or you don’t vote for it … you are not doing your job.”

Gun rights debates have consumed Colorado’s Capitol before. Lawmakers approved a ban on high-capacity magazines and added a background check for firearm transfers in 2013, months after the mass shootings in Aurora and at Sandy Hook Elementary School in Connecticut.

Gun owners’ groups retaliated by pushing successful recall votes against two Democratic state senators who voted for the gun control bills.

The groups again mobilized against the red flag bill, calling Republican co-sponsor Cole Wist “a mole” in the party’s ranks and warning George Brauchler, a district attorney running for attorney general, to withdraw his support.

But Brauchler, who prosecuted the Aurora theater shooter for killing 12 people and injuring 70 others in 2012, called the proposal the most “protective” version of a “red flag” law nationally. By comparison, an Indiana version passed in 2005 lets police confiscate firearms without a warrant and get a judge’s approval afterward, Brauchler said.

“I’m skeptical of giving the government authority like this, but skepticism is not a justification for inaction,” he said.