The U.S. Senate is expected to vote on -- and pass -- a bill to approve the controversial Keystone XL pipeline project on Thursday that would transport nearly 1 million barrels of oil each day from Canada to refineries on the Gulf Coast. But President Barack Obama has said he would veto the Senate bill if the same version passes the House, and Congress doesn’t have enough votes yet to override the president’s threat. Senate Majority Leader Mitch McConnell, R-Ky., told Politico that he asked the president to rethink his veto threat.

If the Keystone vote goes on as planned, it will come one day after the Senate debated a dozen amendments tied to the legislation -- more amendments argued than in all of 2014. Senate Democrats were angered at McConnell and accused him of stifling debate when he moved for a final vote last week but lost a procedural vote. The Senate majority leader said Wednesday’s session showed Washington is starting to shed its image of quashing debate. “We want to get Washington functioning again,” McConnell said on the Senate floor. “And we want to pass common-sense ideas. The Keystone debate is showing how we can do both.”

But it’s unclear in what form the bill will be in if it reached Obama’s desk. The House has yet to vote on the Keystone XL pipeline project, and it may draft its own legislation. If that's the case, Senate and House leaders will form a conference committee and craft a compromise bill that both houses will then have to vote on before sending it to the president.

Obama signaled his intentions to veto the Senate’s Keystone bill on a number of grounds, including environmental concerns and his opinion that the project will fall short of the tens of thousands of jobs touted by Republicans and TransCanada, the Canadian corporation proposing to build Keystone.