(CBS NEWS)-- After months of lobbying, negotiating, and deal-making, the Senate today moved forward with a critical piece of the Obama administration's gun safety proposals, a modest victory for gun control advocates but just one small step toward enacting legislation that would more strictly regulate gun ownership in America.
The Senate voted 68-31 to begin debate on a bill that would significantly expand background checks for gun sales, which has long been a top priority for gun control advocates. Easily surpassing the 60-vote threshold with the support of 16 Republicans, Senate Majority Leader Harry Reid, D-Nev., was able to avert a Republican-led filibuster attempt that aimed to block a full Senate vote of the bill. Two Democrats, Sen. Mark Begich, D-Alaska, and Sen. Mark Pryor, D-Ark., voted no.
The legislation is expected to eventually garner the 50-vote majority needed to pass the full Senate, though the timing of a final vote is unclear.
Republicans opposing the bill are prepared to invoke a rule to force the Senate to wait 30 hours before amendments could be considered. On top of that, Reid said that he expects dozens of amendments to be considered, including several GOP proposals that are doomed to fail but will effectively slow down the process.
"Some of them are going to take a little bit of time," Reid said Wednesday. "We're not going to finish the bill this week. I don't know if we'll finish it next week."
The legislation, though modest in its legislative mandate, is the product of a hard-fought campaign to override the vocal group of Republicans pledging to block any legislation that would at all strengthen regulations on gun ownership. In recent days, the president and vice president have pushed for the bill through personal phone calls to lawmakers and public speeches, while First Lady Michelle Obama delivered an emotional address about gun control in Chicago. Meanwhile, the families of slain Newtown victims have been engaged in a door-knocking campaign in the halls of the Capitol, personally urging members to pass laws that they say would have protected their loved ones.
Wednesday marked a major turning point for the bill's prospects, when Republican Sen. Pat Toomey, R-Pa., announced his support for a version of the bill that would include an amendment he co-sponsored with Sen. Joe Manchin, D-W.Va., a pro-gun Democrat, and which aimed to make the bill more palatable to Republicans.
That compromise, according to Manchin and Toomey, would close the so-called "gun show loophole" and mandate a background check for online gun sales. But it also provides exceptions to the requirement when a gun is transferred as a gift between family members or close friends.
"It was good news," Toomey said Thursday after the vote. "We have an opportunity to try to pass this amendment Sen. Manchin and I are going to offer. We don't know how it's going to turn out but we'll have a chance to get on the bill, have a debate, have the votes, and that's what we should do."
Reid has said he will take this amendment up first, and it is expected to pass without major disruption.
Even so, Sen. Minority Leader Mitch McConnell, R-Ky., reaffirmed Thursday morning his decision to vote against cloture on the gun bill, citing as his opposition the provisions that will be stripped pending the Manchin-Toomey amendment passes.
Pending the final Senate vote, the gun legislation will move to the House, where its fate is yet more uncertain: In the GOP-dominated and sometimes unpredictable chamber, any gun legislation faces an uphill battle. In a press conference this afternoon, Boehner said that while he expected the House to take some action on gun control at some point, he wanted any bill to go through regular order -- suggesting that the bill will not come to the floor unless it has a majority of Republican support.
"Our hearts and prayers go out to the families of these victims and I fully expect that the House will act in some way, shape or form, but to make a blanket commitment without knowing what the underlying bill is, I think, would be irresponsible," he said. "I want this to go through regular order."
On Wednesday, however, Toomey expressed confidence that "substantial numbers of House Republicans that are supportive of this general approach."
"Five days ago, nobody thought we could move forward. And we're moving forward and very, very hopeful about next week," said Sen. Richard Blumenthal, D-Ct., in remarks this afternoon. "But don't underestimate the difficulty of the fight. We have faced an uphill climb every step of the way on this measure and we're prepared for continuing odds against us."
Speaking on the floor after the Senate voted to invoke cloture, Reid thanked the 16 Republicans who voted yes, specifically calling out Sen. John McCain, R-Ariz., for publicly calling on the GOP to allow a debate on the issue. Reid also vowed to hold votes on assault weapons and high-capacity magazine bans.
"I'm grateful to all Republicans who joined with us to allow this debate to go forward. Now the hard work starts," he said. "We're going to have to vote on the Manchin-Toomey amendment. We're going to have to have a vote on assault weapons. Some people love it. Some people hate it. But we're going to have to have a vote on that. We're also going to have to have a vote on the size of clips or magazines."
According to White House Press Secretary Jay Carney, the president spoke by phone today with the families who have been meeting with lawmakers in Washington. Carney said he "congratulated them on this important step forward" and told them that it would not have been possible without their efforts.
Tolleah Price contributed to this report
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