Time is the enemy of gun-control legislation, any advocate will tell you. The outcry for stricter gun laws has always been loudest during moments of national horror, in the hours and days after a massacre, when the anger is raw and the anguish of grieving survivors and families fills the airwaves. That brief window for action quickly begins to close when the public’s attention inevitably drifts to other topics. The opposition mobilizes, and talks break down or simply peter out.

Senator Chris Murphy of Connecticut feared that this all-too-familiar pattern was repeating itself after the May 24 mass shooting in Uvalde, Texas. Despite immense public pressure, the bipartisan group of senators negotiating new gun-safety proposals left Washington before Memorial Day weekend without striking a deal. “Normally when there’s a break in sensitive talks like these, you lose momentum,” Murphy, the Democratic leader of the negotiations, told me this afternoon. On social media, interest in news articles about the slaughter of 19 children and two teachers had already plummeted. By the time Congress returned to session, two weeks had passed.

Something had actually changed this time, however. Rather than dissipate after the recess, the bipartisan negotiations accelerated. Instead of encountering blowback from voters at home, Republican lawmakers reported to Democrats that they felt an urgency from their constituents to act. “Momentum grew,” Murphy said. He sounded as surprised as anyone.

Yesterday, Murphy and 19 of his colleagues unveiled what could become the most significant changes to the nation’s gun laws in more than a quarter century. The framework would expand background checks for people under the age of 21, make it easier for the government to prosecute illegal trafficking of firearms, and provide federal funding to support state-level “red flag” laws, which allow courts to disarm people deemed a danger to themselves or others. Other provisions include billions more in federal support for mental-health programs and additional money for school safety—two elements that Republican negotiators, led by Senator John Cornyn of Texas, prioritized in the talks.

Democrats and gun-control advocates, conditioned to expect vanishingly little from negotiations like these, were pleasantly surprised by the scope of the proposed package. Each provision, Murphy told me, “is less progress than I would have liked. But when you put them all together, it’s a substantial package of changes compared to what I think was possible even 30 days ago.”

The Sandy Hook massacre occurred when Murphy served in the House, barely a month after his first election to the Senate. Nearly a decade later, his earnest indignation about congressional inaction on guns comes with a heavy dose of weary political realism. Half of his job these days seems to be warning against the tendency of voters to become, in his words, “numb” to mass shootings, while the other half is managing the expectations of those same voters about what is possible in divided Washington. Murphy is not the type of Democrat to get your hopes up. “I have had the football pulled out from under me enough times before in these negotiations to be realistic about our prospects for success,” the senator told reporters in Connecticut last week. “I’m sober-minded about our chances.”

So it was notable that not only Murphy but major gun-control groups such as Everytown and Brady were quick to embrace the bipartisan deal as something more than a political fig leaf. Unlike in past negotiations, Murphy told me, the list of viable proposals actually expanded rather than shrank as the talks went on. For example, the provision going after illegal straw purchases, a major priority for big-city mayors looking to stem the flow of guns from other states, was not initially under discussion.

Still, plenty of further-reaching ideas never made it to the table. President Joe Biden blessed the framework even though it included hardly any of the changes he’d sought in his prime-time address earlier this month. The deal has no assault-weapons ban, no limits on high-capacity magazines, no universal background checks, no change in the minimum age required to buy semiautomatic weapons. When I asked a Democratic congressional aide last week whether those policies were under consideration, the reply to each one—no—came with what sounded like the hint of an apology.

Read: ‘I’m, like, this close to snapping’

The passage of time could scale back the compromise even more. The bare-bones framework announced Sunday won the endorsement of 10 Republicans, indicating that if all 50 Democrats go along, the package could clear a Senate filibuster and win passage. But the actual bill has yet to be written, and many of the details—including the question of how much the legislation will cost and where the money will come from—have yet to be ironed out. Senators are hopeful that a bill could be ready for a vote within a few weeks, but similar “framework agreements” have taken much longer to finish in the past.

Murphy and Cornyn have worked together on gun measures several times in recent years. They used as a template their successful talks on smaller tweaks to the background-check system after another Texas mass shooting, the church massacre of more than two dozen people in Sutherland Springs in 2017. Those negotiations resulted in the enactment of the Fix NICS Act as part of a broader spending bill in 2018. The law created carrots and sticks to encourage federal agencies and the military to upload records to the federal background-check system; it also included money that Republicans sought to beef up school security. That the law has not stopped or even meaningfully reduced mass shootings is evident; Cornyn, however, said it has led to the uploading of 11.5 million additional records to the federal background-check system, which represented a 30 percent increase for one database.

In the middle of negotiations last week, Cornyn delivered a speech on the Senate floor that made clear the extent to which the talks were occurring on Republican terms. The negotiators, he said, were not considering any proposals that would expand the background-check system or restrict in any way “the rights of current, law-abiding gun owners and citizens.” There would be no new ban on weapons like AR-15s or limits on ammunition, such as high-capacity magazines. “What I’m interested in is keeping guns out of the hands of those who, by current law, are not supposed to have them,” Cornyn said. The scope of the talks neatly fit an agenda that conservatives, backed by gun-rights groups such as the National Rifle Association, have stuck to for decades: Enforce existing gun laws rather than pass new ones.

Murphy acknowledged that the agreement “remained consistent” with Cornyn’s bottom line. “We’ve been able to meet his requirement while still meeting my requirements, which is that the bill couldn’t be window dressing,” he said. “It had to be substantive changes that could unquestionably save people’s lives.” Murphy argued that limiting the negotiations from the outset proved to be key to their success. “I made it 100 percent clear I wasn’t going to be having fruitless arguments in these meetings about things that couldn’t get 60 votes,” he said. “We were all very focused on what could get 60 votes from the beginning, and that helped the discussions advance.”

The argument that Democrats must now confront from the left is that this deal could set back the effort for a true overhaul of U.S. gun policy. By agreeing to modest changes now, Republicans can tell voters they’ve done something to address gun violence and use that political cover to help win back control of Congress and block more substantial reforms. Murphy defended the framework on the merits, saying that even these compromises would “save thousands of lives.” He’s also advanced a longer-term strategy, one premised on demonstrating to Republicans that supporting new laws won’t doom them with their base voters.

Implicit in his argument is the reality that Democrats won’t have the votes on their own to do what they want anytime soon, and that the kind of atrocity that would jolt Republicans to truly change their mind on the Second Amendment is impossible to contemplate. “Success begets success,” Murphy said. “Even if we never passed another gun-violence bill, I would make the argument that this bill is 100 percent worth it because it is going to make a difference.

“But,” he added, “I also know that it’s a really bad strategy to wait until you can get everything you want. Because that moment almost never comes.”