WASHINGTON -- A bipartisan proposal to expand background checks to more gun buyers is in jeopardy. The pool of potential Republican votes that Democrats will need to push the measure through the Senate has dwindled, and President Barack Obama was calling lawmakers Monday as both sides hunted support for a nail-biting showdown vote expected this week.
At stake is what has become the heart of this year's gun control drive in response to December's killing of children and staff at an elementary school in Newtown, Conn. Supporters consider a broadening of the buyers subjected to background checks to be the most effective step lawmakers can take, and Obama urged near universal checks in the plan he unveiled in January.
"This is America," said Sen. Joe Manchin, D-W.Va., who spoke on the Senate floor as did Sen. Patrick Toomey, R-Pa., promoting the background check compromise they reached last week and on which the chamber will vote. "This is about can we make a difference, can we change something."
Sixteen Republicans voted last week to reject an effort by conservatives that would have blocked the Senate from even considering a broad bill restricting firearms. With that debate now underway, Democrats hope to win enough supporters from this group to gain passage of the first amendment to that bill -- the compromise between Manchin and Toomey -- though more narrowly than Obama had hoped.
So far, seven Republican senators from that group have said they will oppose the Manchin-Toomey plan and one is leaning against it. Combined with the 31 senators who voted against debating the overall gun bill last week, that brings potential opponents of expanding background checks to 39 -- just two fewer than opponents will need to sink the legislation.
"The Toomey-Manchin proposal, while well-intentioned, is not a solution to illegal gun violence. We already have major holes in the current" background check system, Sen. Lindsey Graham, R-S.C., said Monday in a written statement. Graham was among the 16 who voted to allow the debate to begin.
Opponents say expanded checks would violate the Constitution's right to bear arms and would be ignored by criminals. They are forcing supporters of the background check plan to win 60 of the Senate's 100 votes, a high hurdle.
Fifty Democrats and two Democratic-leaning senators voted last week to begin debate. If all of them support the Manchin-Toomey plan -- which is not guaranteed -- they will still need eight additional votes.
So far, three Republicans who backed beginning debate have said they will vote for the Manchin-Toomey plan: Toomey and Sens. Mark Kirk of Illinois and Susan Collins of Maine. A fourth, John McCain of Arizona, said he is strongly inclined to do so.
Sen. Frank Lautenberg, D-N.J., missed last week's vote after saying he was suffering from muscle weakness, but spokesman Caley Gray said he hopes to be in the Senate for votes this week.
Two Democrats, both facing re-election next year in GOP-leaning states, voted against beginning the gun control debate last week: Sens. Mark Begich of Alaska and Mark Pryor of Arkansas. Spokesman Devon Kearns said that Begich is still reviewing the amendment, while aides to Pryor did not immediately return emails and a phone call.
Background checks, designed to keep guns from criminals and the seriously mentally ill, are currently required only for sales handled by the nation's roughly 55,000 licensed gun dealers. The Manchin-Toomey measure would extend that to sales at commercial venues like gun shows and online, while exempting other transactions like those between relatives and friends.
"There's no debate that that's not an infringement of the Second Amendment" right to bear arms, Toomey said.
White House spokesman Jay Carney said the gun legislation was "an absolute priority" and said Obama has been contacting senators, though he declined to say which ones.
But Carney said the vote would be "a difficult challenge." He said that because the Senate had voted last week to begin debating the measure "does not mean we have gotten to where we need to be, which is passage of legislation that is commonsense and that will reduce gun violence in America."
The White House originally had hoped for much more, including a ban on military-style rifles and high-capacity ammunition magazines.
The National Rifle Association said it was running an ad on cable television's Sportsman Channel and online criticizing Mayors Against Illegal Guns for running an ad showing a man holding a gun unsafely as he describes his support for expanded background checks.
"Is it possible he's an actor?" the ad asks, just before showing the NRA's "Stand and Fight" slogan.
Some relatives of the victims of the Connecticut families are planning a return trip to Capitol Hill this week to meet with senators they weren't able to visit on their lobbying trip last week. That trip was partly credited with helping move the Senate to debate the gun bill.
Also scheduled to be lobbying lawmakers this week are former Rep. Gabrielle Giffords, D-Ariz., and her husband Mark Kelly, the retired astronaut. She was severely wounded in a 2011 mass shooting in Tucson, Ariz.
The Manchin-Toomey deal also would expand some firearms rights, easing some restrictions on transporting guns across state lines and protecting sellers from lawsuits if buyers pass a background check but later use a gun in a crime.
The compromise is an amendment to broader gun control legislation to strengthen laws against illegal gun trafficking and to slightly increase school security aid.