WASHINGTON — A bipartisan deal seems imminent on expanding background checks to more gun buyers, an agreement that could build support for President Barack Obama's drive to curb firearms violence.
Meanwhile, the Senate is ready for an opening vote on restricting guns as Majority Leader Harry Reid, D-Nev., set a roll call for Thursday on starting consideration of the firearms legislation. Odds are growing that Democrats will win enough Republican support to thwart an effort by conservatives and Senate Minority Leader Mitch McConnell, R-Ky., to block consideration from even starting.
"I hope Republicans will stop trying to shut down debate and start engaging in the tough issues we were sent to Washington to tackle," Reid said.
Together, the developments were a boost for gun control advocates battling for restrictions in the wake of December's shootings that killed 20 first-graders and six staffers at an elementary school in Newtown, Conn.
Even so, the ultimate fate of gun legislation remains unclear, clouded by opposition from many Republicans and moderate Democrats in the Democratic-led Senate and the Republican-run House. Many critics say the proposal would violate the Second Amendment right to bear arms and burden law-abiding gun owners.
"We should focus law enforcement resources on the bad guys," said Sen. Ted Cruz, R-Texas.
Sens. Joe Manchin, D-W.Va., and Patrick Toomey, R-Pa., were expected to announce a background check compromise on Wednesday. Subjecting more firearms purchases to federal background checks has been the chief goal of Obama and gun control supporters, who promote the system as a way to prevent criminals and other risky people from getting the weapons.
After weeks of negotiations, Manchin and Sen. Chuck Schumer, D-N.Y., told reporters late Tuesday that a gun control agreement was close.
The emerging deal would expand required background checks for sales at gun shows and online but exempt transactions like face-to-face, noncommercial purchases, said Senate staffers and lobbyists, who spoke on condition of anonymity to discuss the private talks. Currently, the checks are required only for sales handled through licensed gun dealers.
Though many details of the emerging agreement were unclear, Manchin and Toomey are among their parties' most conservative members and a deal could make it easier for some hesitant senators to support the background check measure, at least for now.
Some Republicans might vote to begin debate on the legislation but eventually oppose the measure on final passage. Other parts of Obama's gun effort already seem likely to face defeat, including proposed bans on assault weapons and high-capacity ammunition magazines.
The gun legislation Reid wants the Senate to debate would extend the background check requirement to nearly all gun sales. Assuming the deal between Manchin and Toomey is completed, Reid would try to replace that language with their agreement once debate begins, a move that would require a vote.
The overall gun bill also tightens federal laws against illegal gun sales and slightly increases federal aid for school safety.
Thirteen conservatives have signed a letter saying they will block consideration of the measure, and McConnell said he will back that move. That will force Democrats to round up 60 votes to overcome the conservatives.
At least eight Republicans have said they want to begin debate or have indicated a willingness to consider it, a number that would be expected to grow if the background check agreement proves successful.
The eight are Sens. John McCain of Arizona, Lindsey Graham of South Carolina, Tom Coburn of Oklahoma, Johnny Isakson and Saxby Chambliss of Georgia, Susan Collins of Maine, Roy Blunt of Missouri and Mark Kirk of Illinois.
Some moderate Democrats were remaining noncommittal and could oppose opening the gun debate. They include Sens. Mark Begich of Alaska and Mark Pryor of Arkansas, who are seeking re-election next year. There are 53 Senate Democrats and two independents who lean Democratic.
Amid the maneuvering, relatives of some Newtown victims are lobbying to support gun curbs. And Obama has been calling senators from both parties to push for the gun bill.
"People should listen to what we have to say and move the debate forward," said Mark Barden, who lost his 7-year-old son, Daniel. "It's not just about our tragedy. Lots of kids are killed every day in this nation. We have to help lead the change."
The National Rifle Association opposes Obama's effort and is urging its members — it claims nearly 5 million — to tell lawmakers of their opposition.
In GOP-heavy Louisiana, the NRA asked members to contact Democratic Sen. Mary Landrieu, who is seeking re-election next year. "The future of our Second Amendment rights are at stake," the mailing said.
Counteracting that has been an effort by Mayors Against Illegal Guns, one of whose leaders is billionaire New York Mayor Michael Bloomberg. It said it will keep track of key gun-related congressional roll calls and make the information available to voters and contributors — a tactic long used by the NRA and other groups.
Associated Press writers Nedra Pickler, Jim Abrams, Andrew Miga and Henry C. Jackson contributed to this report.