Here are the key moments you missed from the marathon gun vote protest Democrats staged on the House floor. The sit-in stretched from June 22 into the morning hours of June 23. (Jenny Starrs/The Washington Post)

Gun control advocates were predicting Thursday that they had significantly altered the dynamics of the national gun-control debate, crediting recent episodes of unusual political theater on Capitol Hill.

Tempering that optimism, however, was continued inaction by Congress on actual gun legislation. The House adjourned in the early hours Thursday as GOP leaders sought to short-circuit a remarkable on-floor protest by Democrats. Hours later, the Senate stalled on a bipartisan compromise proposal to keep guns out of the hands of suspected terrorists.

But gun-control supporters believe they have turned a corner toward building greater public support for their cause.

“A fire has been lit across our nation” said Rep. Joseph Crowley (D-N.Y.) “The people have seen the Democratic caucus stand up and fight — not just do the regular routine. We’re not going to sit back and do nothing anymore.”

The new confidence follows a pair of high-profile, social-media-fueled protests led by Democrats on Capitol Hill in recent weeks. First Sen. Chris Murphy (D-Conn.) led a 15-hour filibuster last week that set the stage for a series of gun-related votes. Then, on Wednesday, House members waged a sit-in protest on the House floor that stretched to 26 hours by the time they left.

“Members have just become totally tired and frustrated of every time we have a heart-wrenching tragedy in our country from gun violence,” said House Minority Leader Nancy Pelosi (D-Calif.), citing the mass shootings in Orlando, Charleston, S.C., and Newtown, Conn.

Lawmakers remained in the well of the House chamber for hours, some wrapped in blankets and gripping paper coffee cups as Wednesday became Thursday, taking turns excoriating Republicans for not taking action to address gun violence. Microphones and official House cameras were switched off under the House rules; lawmakers instead live-streamed the protest from their cellphones to thousands of viewers outside the House galleries.

Republicans moved to take back control of the floor in a series of dramatic overnight clashes. Shortly after 3 a.m., they moved to immediately adjourn until after the July 4 holiday — two days sooner than planned — in order to end the sit-in. Democrats stayed on the floor another 10 hours.

House Speaker Paul D. Ryan (R-Wis.) harshly criticized the Democratic sit-in at a news conference Thursday, declaring it a gimmick that undermined the institution.

“We can disagree on policy, but we do so within the bounds of order and respect for the system; otherwise, it all falls apart,” he said. “We are not going to allow stunts like this to stop us from carrying out the people’s business.”

But it was clear that the “stunt” achieved its objectives for the Democrats, unifying and energizing the often-fractious minority that has tended to greet each new gun-related tragedy with a sense of resignation that no effective action was possible, given the political potency of gun rights advocates — particularly the National Rifle Association.

Some veteran Democratic lawmakers called the effort unprecedented and expressed optimism that Republicans would eventually have to capitulate. 

The sit-in episode took on the cast of a 1960s civil rights protest. It was partly led by Rep. John Lewis (D-Ga.), who a half-century ago was physically beaten in many of them.

“Thank you for getting in trouble — good trouble,” Lewis told colleagues Wednesday night. “Sometimes by sitting down, by sitting in, you’re standing up.”

Advocacy groups have seized on the Democrats’ recent efforts to draw attention on Capitol Hill. On Thursday, they began strategizing ways to pressure lawmakers in their home districts during the July 4 recess.

Everytown for Gun Safety, a group backed by former New York mayor Michael Bloomberg, plans to deploy volunteer activists to legislators’ town-hall meetings, though it is still determining which lawmakers to focus on.

The group said its members made more than 181,000 calls to the House over a 24-hour span to express support for the sit-in and that Facebook and Twitter posts by its members reached more than 10 million people.

“The environment has changed; the atmosphere has changed,” said Brina Milikowsky, Everytown’s chief strategy officer. “Leaders can’t run away from the fact that Americans are calling for reforms, and the majority are calling for the measures that we’ve been pushing.”

Another group, the Brady Campaign to Prevent Gun Violence, said it generated about 7,200 calls to Ryan’s office. A spokesman said the group is now looking at ways its state chapters can engage lawmakers at home during the holiday recess.

The NRA did not respond to requests for comment Thursday. But the group tweeted several times in recent days, urging its grass-roots network to call and email senators to oppose new gun-control measures.

The Senate delivered a reality check to gun-control supporters Thursday when a bipartisan effort to keep guns away from suspected terrorists failed to garner the 60 votes needed to advance. That amendment, brokered by Sen. Susan Collins (R-Maine), won the backing of a handful of Republicans but also earned the opposition of the NRA and the American Civil Liberties Union, which said it failed to protect the rights of law-abiding Americans.

The compromise survived a test vote on a 52-to-46 margin. But without the 60 votes necessary to vault procedural hurdles, Senate GOP leaders indicated they were ready to move on to other business.

The last major gun-control measure passed the Senate 22 years ago, banning assault weapons as part of the 1994 crime bill, and every significant effort since then has failed in the face of NRA opposition.

But Democrats still claimed a win with Thursday’s vote. “Even though it wasn’t a big victory, it was a victory,” said Senate Minority Leader Harry M. Reid (D-Nev.), calling it the first time the NRA lost a vote in the Senate since 1994.

Catherine Ho, Paul Kane, Ed O’ Keefe and Kelsey Snell contributed to this report.