In a surprise move, Senate Republicans will agree to allow a simple majority vote on the Democrats' tax cut bill in exchange for a majority vote on an alternative GOP plan to extend all the Bush tax cuts, Senate aides in both parties said.
Under the agreement, the Democratic bill -- which would extend the Bush tax cuts for couples earning less than $250,000 a year -- will not be filibustered. The GOP bill would then receive a separate vote that is expected to fail along party lines. Voting, originally scheduled for 2:15 p.m., is scheduled to begin at 4 p.m.
Democratic leadership aides said they have the votes to pass the bill. Vice President Joe Biden will be presiding over the vote in case there is a tie.
Sen. Kay Hagan, D-N.C., is expected to miss the vote to attend a funeral. Sen. Mark Kirk, R-Ill., who is still recuperating from a stroke, remains absent, creating the chance of a tie vote.
Senate Republican Leader Mitch McConnell had previously blocked Democratic requests to vote under a majority vote threshold. But leadership aides said McConnell and Democratic Senate Majority Leader Harry Reid were finalizing a unanimous consent agreement for majority votes on both parties' plans.
A GOP leadership aide said the party sees an advantage in forcing vulnerable Democrats, including members up for reelection this year and in 2014, to vote on the "direct question" of whether to support or oppose raising taxes for wealthier Americans and some small businesses, rather than voting on only a procedural motion to move to the Democratic bill.
"Democrats are in a very difficult spot and the light is shining directly on their decision today," the aide said.
Democrats believe passing their bill will give them eventual leverage on the House, where Republicans next week expect to pass an extension of all the Bush tax cuts.
And Senate Republicans say they are essentially calling Reid's bluff. They argue that making Democrats take a difficult vote is more important than the symbolic victory Democrats' gain by passing the bill, which will never advance in the House.
This post has been updated. Sen. Kay Hagan is present for the votes. Originally published at 12:59 p.m