Connecticut Sen. Chris Murphy launched a talking filibuster before noon Wednesday, saying he intended to give an extended speech to protest inaction on gun violence.
He was still speaking 12 hours later, having received help from many of his Democratic colleagues hoping to offer gun amendments to a spending bill that funds federal law enforcement agencies, including the Department of Justice, being debated in the Senate.
Murphy is holding up action, saying Democrats and Republicans should "not proceed with debate on amendments to this bill until we have figured out a way to come together on, at the very least, two simple ideas.”
"I will remain on the Senate floor until we get some signal, some sign that we can come together," Murphy said as he evoked the Sandy Hook Elementary School shooting on Dec. 14, 2012.
Murphy began speaking at 11:21 a.m., and by Senate rules, he has to stand at his desk to maintain control of the floor. When asked by another senator how he was feeling just before 7:30 p.m., Murphy said rehabilitation from a back injury in his 20s had helped him build up endurance. The senator didn't make note of hitting the 12-hour mark.
Murphy is seeking a vote on legislation from Sen. Dianne Feinstein, D-Calif., that would let the government bar sales of guns and explosives to people it suspects of being terrorists. Feinstein offered the amendment in December — a day after an extremist couple killed 14 people in San Bernardino, California — but the Republican-run Senate rejected the proposal on a near party-line vote.
Attempts at compromise appeared to collapse within hours of surfacing in the Senate Wednesday, underscoring the extreme difficulty of resolving the divisive issue five months to the election. Sen. Dianne Feinstein, D-Calif., who had been involved in talks with Sen. John Cornyn, R-Texas, said there was no resolution.
The Orlando shooter was added to a government watch list of individuals known or suspected of being involved in terrorist activities in 2013, when he was investigated for inflammatory statements to co-workers. But he was pulled from that database when that investigation was closed 10 months later.
Murphy also wants a vote to expand background checks.
Joining him on the Senate floor is fellow Conn. Democrat, Sen. Richard Blumenthal. The two senators, galvanized by the 2012 shooting that killed 20 children and six adults at an elementary school in their state, urged a ban on assault weapons and better controls on who can buy guns.
New Jersey Sen. Cory Booker joined Murphy and Blumenthal, stressing the need for such gun control measures, particularly in light of Sunday's shooting in Orlando that left 49 victims dead and 53 injured.
"I've cleared my entire day...so I can stay on this floor and assist Senator Murphy," Booker said.
The former mayor of Newark said many senators who will take to the floor Wednesday in support of Murphy's filibustering effort have the word "enough" in their hearts.
"What we're seeking is not radical. What we're seeking is not something partisan. What we're seeking is common sense," Booker said in an impassioned speech.
New York Sen. Chuck Schumer chastised the Senate, calling the legislative chamber a "shameful" body in "it's obedience to the gun lobby and not doing the most reasonable things most Americans support."
In a statement Wednesday, the National Rifle Association said it did not believe terrorists should be allowed to "purchase or posses firearms." But noted that "at the same time, due process protections should be put in place that allow law-abiding Americans who are wrongly put on a watchlist to be removed."
The pro-gun lobbying group has been accused of influencing lawmakers from passing such restrictions on firearm purchases, arguing that using a terror watch list as a basis for barring sales infringes on Second Amendment rights.
The election-year fight over gun control pits strong proponents of the 2nd Amendment right to bear arms against lawmakers arguing for greater restrictions on the ability to obtain weapons. Since the Sunday morning shooting in Orlando, Democrats have revived their push for legislation.
The Associated Press contributed to this report.