A bipartisan group of senators on Sunday announced an agreement had been reached -- though in principle only -- on new legislation meant to address the country's ongoing gun violence, including the recent Uvalde, Texas, elementary school shooting.
The deal, in the works for weeks, has the support of at least 10 Republicans in the Senate, which is the number needed to avoid a filibuster.
If passed, the proposal would be the first major gun law to make it through Congress in years.
Among other things, the agreement would provide funding for mental health (including behavioral health centers) and incentives for the creation of so-called "red flag" laws to remove firearms from people who are a danger to themselves or others; increase money for school safety; and strengthen the federal background check system as it relates to convicted domestic violence abusers or those with restraining orders.
MORE: Lawmakers note 'profile' of mass shooters -- mostly young men -- as they weigh gun compromisePotential gun owners under 21 would also be subject to "an investigative period to review juvenile and mental health records, including checks with state databases and local law enforcement," the bipartisan group said Sunday.
Twenty senators released a statement confirming the deal, saying in part: "Today, we are announcing a commonsense, bipartisan proposal to protect America's children, keep our schools safe, and reduce the threat of violence across our country. Families are scared, and it is our duty to come together and get something done that will help restore their sense of safety and security in their communities."
The 20 lawmakers -- double the initial bipartisan group who restarted negotiations late last month -- are Sens. Richard Blumenthal of Connecticut, Roy Blunt of Missouri, Cory Booker of New Jersey, Richard Burr of North Carolina, Bill Cassidy of Louisiana, Susan Collins of Maine, Chris Coons of Delaware, John Cornyn of Texas, Chris Murphy of Connecticut, Lindsey Graham of South Carolina, Martin Heinrich of New Mexico, Mark Kelly of Arizona, Angus King of Maine, Joe Manchin of West Virginia, Rob Portman of Ohio, Mitt Romney of Utah, Kyrsten Sinema of Arizona, Debbie Stabenow of Michigan, Thom Tillis of North Carolina and Pat Toomey of Pennsylvania.
The carefully calibrated changes in the deal -- mixing some modest gun restrictions with a focus on schools and social services -- reflect the evenly divided Senate, requiring any law to attract at least 10 Republican votes.
Notably, the new proposal does not address major Democratic priorities such as blocking access to assault-style weapons for people under 21 -- a ban that President Joe Biden had backed in a recent primetime address to the nation but which was taken off the table among the Senate negotiators. This comes despite Senate Minority Leader Mitch McConnell privately expressing a willingness to support such a move, sources told ABC News.
Conservatives have long resisted gun reform, arguing in part that the laws are ineffective and that they trespass the guarantees of the Second Amendment.
MORE: Behind the scenes of Congress' gun talks: Fragile optimism for an incremental dealBut the rising tide of gun violence -- like the mass shootings in Uvalde and in Buffalo, New York, before that and in Boulder, Colorado, before that; and many more -- had increased the urgency of some kind of proposal, lawmakers involved have said.
Senate Majority Leader Chuck Schumer, of New York, said Sunday he supported the new agreement, calling it "a good first step," and would be scheduling a vote on it as soon as the legislative text was complete.
"We must move swiftly to advance this legislation because if a single life can be saved it is worth the effort," he said.
House Speaker Nancy Pelosi said last week she would take up a Senate bill "if it's life-saving and can make a difference and they have bipartisan support for it, then we would welcome it even though it won't be everything that we want." In a statement Sunday, she said she supported the new deal but that "we are continuing to fight" for broader restrictions such as those on the age to purchase assault weapons.
A more specific timeline remained unclear and previous such deals show it could be weeks before a draft law is ready, as was the case with the infrastructure package passed last year.
A GOP aide involved in the negotiations stressed that the agreement was not on all of the details, which will be critical for Republicans, particularly the firearms-related provisions. One or more of these provisions could be dropped, the aide said.
Sen. McConnell on Sunday signaled his tentative support for the talks as well.
"The principles they announced today show the value of dialogue and cooperation," he said in a statement. "I continue to hope their discussions yield a bipartisan product that makes significant headway on key issues like mental health and school safety, respects the Second Amendment, earns broad support in the Senate, and makes a difference for our country."
MORE: Where do gun reform talks stand in Congress after Biden's address?In a pair of statements, President Joe Biden and Vice President Kamala Harris acknowledged that the deal did not align with their own goals but that they believed it would still be a meaningful deterrent to future violence.
"It does not do everything that I think is needed, but it reflects important steps in the right direction," Biden said, lauding the "tireless work" of the Senate group. "Each day that passes, more children are killed in this country: the sooner it comes to my desk, the sooner I can sign it, and the sooner we can use these measures to save lives," he said.
Gun control advocates and anti-gun violence groups likewise backed the announced framework while arguing there was more still to do.
"In a less broken society, we would be able to require background checks every single time someone wants to buy a gun, and we would ban assault rifles outright. But if even one life is saved or one attempted mass shooting is prevented because of these regulations, we believe that it is worth fighting for," March for Our Lives co-founder David Hogg, who was a student at the Stoneman Douglas High School mass shooting in 2018, said in a statement.
Former Arizona Rep. Gabby Giffords, who survived an assassination attempt 11 years ago that killed six others, on Sunday wrote on social media that she believed the deal was necessary if incomplete.
"If carefully drafted and passed into law, this framework would be a lifesaving step forward," she wrote.
Pelosi echoed that last week, telling reporters that in her view "it's about guns. And it's about other things, too, but we cannot avoid the fact that it's about guns: their availability, at what age [people can possess them]."
The Senate has repeatedly tried and failed to agree on major gun legislation, with talks periodically restarted in the wake of various shootings. The Democratic House separately took up its own gun control measures in the wake of the Uvalde killings, though the Senate has shown little interest in those proposals.
With the shadow of polarization looming over the latest negotiations, Republican Sen. Cornyn and Democratic Sen. Murphy -- the latter perhaps the chamber's most outspoken supporter of gun control -- reconvened a group seeking some kind of deal.
The lawmakers met remotely and in person, talking via phone and text, including during a brief recess. Biden, having taken a more direct role in previous negotiations important to his administration, this time said he would remain on the sidelines.
"It's inconceivable to me that we have not passed significant federal legislation trying to address the tragedy of gun violence in this nation," Murphy told ABC "This Week" co-anchor Jonathan Karl in late May. "The pace of everyday gun violence has dramatically escalated over the past two years."
"My hope is that this time is different," Murphy said then. "I get it. Every single time, after one of these mass shootings, there's talks in Washington and they never succeed. But there are more Republicans interested in talking about finding a path forward this time than I have ever seen since Sandy Hook."
Specifics still taking shape
With those involved in the deal saying specifics are still being hashed out, some of the senators involved have previously addressed how they would like to see certain provisions implemented -- and they have been open about where disagreements remain, including with funding.
Regarding the possible expanded use of juvenile records in background checks, Sen. Tillis said last week: "The biggest problem you have right now with people 18 -- really under 21 -- is you don't have a lot of information that goes back to their juvenile records. So, I think the talk is less about raising the age and more about making sure you have all the information you need to make a decision."
Tillis was one of four in a core group of negotiators -- along with Cornyn, Murphy and Sinema -- aiming to strike the right balance on a new law.
Negotiators have been assessing how to allow background check access to juvenile records that contain felony or other dangerous offenses. But this has proved one of the most difficult areas in the talks, according to two senators familiar with the matter.
Tillis said last week the group was looking at different "engagement models" in states; some already upload juvenile records into a system that would be accessed by a background check. But Tillis said his group was "trying to inventory and figure out" which records to sweep into the federal system. "It's not like we're going to take a huge swath of all juvenile records," he said. "What we're trying to do -– the only part of the juvenile record we're interested in are offenses that map to disqualifying convictions as an adult."
Tillis said that in some instances, though, there might be "underlying circumstances, like two kids fighting at a football game" that would have to be separated out as not meriting a flag in a background check.
Someone 18 to 21 who might want to purchase an assault rifle would have a the right to adjudicate any disagreement with any background check failure as anyone would in the current system, according to Tillis.
Overall funding in the bill could also prove problematic, as members have appeared at odds over whether the billions required to implement the proposed policies would come from new federal funding or taken back from already-allocated funds, such as any leftover from the pandemic-era American Rescue Plan.
Cassidy has said he would insist that any new funding be paid for with spending cuts.
But Blumenthal, who has been leading negotiations on the program to incentivize states to develop "red flag" laws, previously said that "there is, in my view, very little justification for requiring an offset dollar for dollar. What we're dealing with here is a national crisis that has to be addressed right away with new money, not taking it away from other law enforcement."
ABC News' Mariam Khan contributed to this report.