Following attention from prominent Democrats, and an announcement that gun control groups had donated over $100,000 to fighting the effort to recall Rep. Tom Sullivan (D), backers of the recall campaign have ended their pursuit.

GOP Vice Chairwoman Kristi Burton Brown formally submitted the petition . In a Facebook post she wrote, "While we are pulling the recall today to focus on other essential efforts, Sullivan does not get a free pass. 2020 is the year to oust him, with the support of voters who now know how extreme he is."

The Colorado Secretary of State's office confirmed the end of the effort.

Sullivan predicted that this is how the recall effort would end, and that the constituents he had talked to while canvassing had been outraged.

"This is a huge day," Sullivan said. "No one has ever stopped one of these recalls before. We're the first ones. We stopped this dead in its tracks and it's not going to go on anymore."

"I can take a break. I can catch my breath. Breathe deeply. But I know that the struggle continues. There's still work to do and I'm up to the challenges."

Much of the signature gathering, especially by the gun rights group Rocky Mountain Gun Owners focused on Sullivan's controversial Extreme Risk Protection Order legislation . Gov. Jared Polis signed the bill into law in April . It allows family members and law enforcement to petition a judge to have guns temporarily taken away from people deemed to pose a significant risk to themselves or others.

"It's clear from our work on the ground in HD-37 that Sullivan is out of step with his constituents and Colorado at-large," wrote Rocky Mountain Gun Owners Executive Director Dudley Brown in a Facebook post announcing the group's suspension of gathering signatures.

"Tom Sullivan's socialist voting record and radically anti-gun positions will be a central discussion piece of the 2020 General election."

But not all Republicans and gun rights supporters got behind this recall effort.

Laura Carno is executive director of FASTER, a group that trains armed school staff. She was an active participant in the successful 2013 recall effort , launched over a package of gun control bills passed in the aftermath of the Aurora theater shooting. Months after those votes, two democrats lost their seats.

"It feels very different to me than the one I participated in,"Carno said. "Most folks know he [Sullivan] lost his son in the Aurora theater shooting. He said 'I'm running for office, I'm gonna offer and pass every gun control bill that I possibly can.' He was very transparent about that," she said.

"The people from his district voted for him knowing all of that so to go back to that same electorate and say 'Hey the guy who said he'd do these things, he did them, so we should get rid of him.' I just think that's a harder uphill slog."

Sullivan's Extreme Risk Protection Order law is set to take effect in January, if it survives a legal challenge brought by Rocky Mountain Gun Owners.