Sen. Chris MurphyChristopher (Chris) Scott MurphyMichigan Dem: Detroit-style pizza 'sweeping the nation' Overnight Cybersecurity: Senators want info on 'stingray' surveillance in DC | Bills to secure energy infrastructure advance | GOP lawmaker offers cyber deterrence bill Overnight Health Care: GOP pushes stiff work requirements for food stamps | Johnny Isakson opens up about family's tragic loss to opioids | Republicans refuse to back vulnerable Dem's opioids bill | Dems offer new public option plan MORE (D-Conn.) and other Democrats have taken over the Senate floor to call for tougher gun control laws and specifically action on keeping people on terrorist watchlists from buying firearms.

“I'm prepared to stand on this floor and talk about the need for this body to come together on keeping terrorists away from getting guns ... for, frankly, as long as I can, because I know that we can come together on this issue,” Murphy said in beginning the filibuster on Wednesday.

ADVERTISEMENT
Murphy began speaking at about 11:20 a.m., and the filibuster was still going more than 12 hours later.

Other Democrats who joined him included Sens. Richard Blumenthal (Conn.), Joe ManchinJoseph (Joe) ManchinMcConnell hits back at 'ridiculous' Chinaperson remark Overnight Defense: New allegations against VA nominee | Pompeo vote set for Thursday | Work begins on defense policy bill | Measures push space corps, pay bump for troops Pompeo set to be confirmed on Thursday MORE (W.Va.), Patrick LeahyPatrick Joseph LeahyCongress should build on the momentum from spending bill Overnight Tech: Zuckerberg grilled by lawmakers over data scandal | What we learned from marathon hearing | Facebook hit with class action lawsuit | Twitter endorses political ad disclosure bill | Uber buys bike share Overnight Cybersecurity: Zuckerberg faces grilling in marathon hearing | What we learned from Facebook chief | Dems press Ryan to help get Russia hacking records | Top Trump security adviser resigning MORE (Vt.), Al FrankenAlan (Al) Stuart FrankenFranken to make first public appearance since resignation Overnight Cybersecurity: Fallout from Comey memos | IG reportedly investigating memos over classified info | DNC sues Russia, Trump campaign | GOP chair blasts FDIC over data security Why Smokin' Joe leads the pack of 2020 Democratic hopefuls MORE (Minn.), Cory Booker (N.J.), Bill NelsonClarence (Bill) William NelsonTucker Carlson criticizes GOP for campaigning against Clinton: She ‘doesn’t run anything’ Senators debate new business deduction, debt in tax law hearing Winners and losers from Jim Bridenstine’s confirmation as NASA administrator MORE (Fla.), Dick DurbinRichard (Dick) Joseph DurbinGOP moves to cut debate time for Trump nominees Senators to Trump: Let Mueller finish Russia probe Democrats fret over GOP changes to Mueller bill MORE (Ill.), Charles SchumerCharles (Chuck) Ellis SchumerCan Mueller be more honest than his colleagues? Throwing some cold water on all of the Korean summit optimism House Republicans push Mulvaney, Trump to rescind Gateway funds MORE (N.Y.), Ben CardinBenjamin (Ben) Louis CardinSenators debate new business deduction, debt in tax law hearing The Hill's 12:30 Report Dems give muted praise to Pompeo-Kim meeting MORE (Md.) and Ed MarkeyEdward (Ed) John MarkeyDem senators demand Trump explain ties to Koch brothers Overnight Cybersecurity: Senators want info on 'stingray' surveillance in DC | Bills to secure energy infrastructure advance | GOP lawmaker offers cyber deterrence bill Overnight Tech: Alleged robocall kingpin testifies before Congress | What lawmakers learned | Push for new robocall rules | Facebook changes privacy settings ahead of new data law | Time Warner CEO defends AT&T merger at trial MORE (Mass.).

It also won support from presumptive Democatic presidential nominee Hillary ClintonHillary Diane Rodham ClintonKim Kardashian West defends Kanye on Trump: 'He's a free thinker, is that not allowed?' Trump comments on Fifth Amendment resurface after Cohen filing The 'Handmaid's Tale' liberal feminists created MORE and her rival, Sen. Bernie SandersBernard (Bernie) SandersGillibrand unveils bill to offer banking services at post offices Webb: Bernie Sanders announces his ‘new’ communism jobs, health-care plan A new progressive standard on campaign cash: It can't come from corporations MORE (I-Vt.).

The Senate is currently considering an appropriations bill for the Commerce and Justice departments and science programs. Though no votes are currently scheduled, the senators are blocking any amendments to the bill.

"I don't think we should proceed with debate on amendments to this bill until we have figured out a way to come together," Murphy said, referring to the spending bill.

The Democrats are also technically blocking Majority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellGOP moves to cut debate time for Trump nominees McConnell hits back at 'ridiculous' Chinaperson remark GOP senator: 'We were there' on immigration before talks got derailed MORE (R-Ky.) from ending debate on the legislation, though a spokesman shot down any speculation that the Republican leader would have tried to wrap up work on the spending bill Wednesday.

Democrats have given no indication how long they plan to hold the Senate floor. Chris Harris, a spokesman for Murphy, said Democrats launched the talkathon because the senator will no longer accept “inaction or half measures in the face of continued slaughter.”

The effort comes three days after the deadliest mass shooting in U.S. history. A gunman armed with a Sig Sauer MCX rifle and a handgun on early Sunday killed 49 people at an Orlando nightclub. 

Murphy is well-known for his support for tougher gun control laws. One of America's most shocking gun crimes occurred in his home state in Newtown, where 20 children and six adults were shot to death at Sandy Hook Elementary School.

"I can't tell you how hard it is to look into the eyes of the families of those little boys and girls who were killed in Sandy Hook and tell them that almost four years later we've done nothing, nothing at all," Murphy said. 

Since the Orlando attack, Democrats have put a renewed focused on legislation meant to block the sale of guns to people on terrorist watchlists. 

An effort to move legislation was previously blocked last year. 

Sen. Ben Sasse (Neb.) was the first Republican senator to join Murphy and other Democrats, asking a question about the government's terror watchlists.

"I'm familiar with the terrorist screening database. There are a series of lists that fall from the database, but I don't think there's any such thing as 'the terrorist watchlist,' and I certainly don't understand what due process rights would apply," Sasse said.

Sasse's comment reflects a central problem Republicans have with a proposal from Sen. Dianne FeinsteinDianne Emiel FeinsteinOvernight Cybersecurity: DHS cyber nominee vows to make election security 'top priority' | CIA to allow lawmakers to review classified info on Haspel | Dems raise security concerns about Trump's phone use Democrats fret over GOP changes to Mueller bill Feinstein introduces bill allowing DHS to quickly remove 'compromised software' MORE (D-Calif.) that would give the attorney general broad authority to block people on watchlists from being able to buy guns or explosives. 

Republicans argue that could deny constitutional rights to Americans who aren’t actually tied to terrorism.

Instead, Sasse and most Republicans support an alternative proposal by Sen. John CornynJohn CornynGOP moves to cut debate time for Trump nominees Republicans want Trump’s VA nominee to withdraw Senators to Trump: Let Mueller finish Russia probe MORE (R-Texas) that would allow the attorney general to delay suspected terrorists from getting a gun for up to 72 hours while seeking a court order to stop the sale.

Sen. Pat Toomey (R-Pa.), who faces a tough reelection bid, came to the Senate floor urging his colleagues to compromise. 
 
"There's an obvious opportunity here, guys, to work together and find the solution," he said. "What I'm suggesting is let's get to work here." 
 
Toomey on Wednesday criticized the Feinstein measure as "badly flawed." But he also said that Cornyn's proposal, which he previously voted for, likely didn't give enough leeway to the attorney general. 
 
He made the comments after Democratic Senate candidate Katie McGinty, who is hoping to unseat Toomey, pressured the GOP senator to back the Feinstein legislation during a press conference Tuesday. 
 
Wednesday afternoon, Toomey said he planned to introduce a compromise bill Thursday aimed at combining aspects of both the Feinstein and Cornyn proposals.
 
Toomey's legislation would require the attorney general to create a list of "likely terrorists" that could be blocked from buying guns. The list would then be submitted to the Foreign Intelligence Surveillance Court, which would review it annually and remove any Americans inadvertently included, according to a summary of the forthcoming bill from his office.

Updated at 11:35 p.m.