WASHINGTON -- Legislation to force the approval of the Keystone XL pipeline picked up support Thursday as more Democratic senators signed on to Sen. Mary Landrieu's effort.

On Wednesday, the Senate struck a deal to debate and a vote, probably Tuesday, on the measure from the Louisiana Democratic incumbent. The House plans to vote this Friday on a similar bill to force the pipeline's approval, sponsored by Rep. Bill Cassidy (R-La.).

The lame-duck votes on Keystone come as Landrieu and Cassidy are facing one another in a runoff election for her Senate seat on Dec. 6. Landrieu has said that her bill isn't about electoral politics, she just wants to see Keystone approved. In a press conference Wednesday evening, the current chair of the Senate Energy and Natural Resources Committee expressed support for her rival's bill. "Hallelujah!" she said. "We have now even a clearer path to victory."

The Senate can probably muster 60 votes if most of the Democrats who have previously endorsed the pipeline vote in its favor. Landrieu's bill has 10 Democratic co-sponsors, and a handful of other Democrats have previously expressed support for Keystone and could vote for the bill. The Hill reported Thursday that Sen. Tom Carper (D-Del.) said he would support it, and John Rizzo, communications director for Sen. Bob Casey, told The Huffington Post Thursday that the Pennsylvania Democrat would also vote yes. Their votes would give Landrieu at least 58 votes, with several other Democrats still on the fence.

On Friday, Energy & Environment Publishing got confirmation from the office of Sen. Michael Bennet (D-Colo.) that he would also vote for the bill, bringing the total number of anticipated "yes" votes in the Senate to 59.

The Obama administration has delayed a final decision on Keystone until a court issues a ruling on a legal challenge in Nebraska to the pipeline's proposed route through the state.

The Senate's Keystone measure opens up interesting political fault lines, pitting a number of Senate Democrats against the president's stated desire to let the decision-making process play out within the State Department.

The White House has indicated that Obama would likely veto such a measure should it pass Congress, but has yet to say as much outright. "It is the view of the administration that that process should continue, and that that's the proper venue for determining whether the project should move forward," said White House spokesman Josh Earnest Thursday. "There [have] been other legislative proposals that have been floated to try to influence the outcome of this decision about the construction of the pipeline. The administration, as you know, has taken a dim view of these kinds of legislative proposals in the past."

Republicans , meanwhile, are making moves to support their candidate in the runoff. Incoming Senate Majority Leader Mitch McConnell (R-Ky.) on Wednesday promised Cassidy a seat on the Energy and Natural Resources Committee if he wins. Such a promise could reassure Louisiana voters that they would retain a voice on the powerful Senate energy committee come January.

It seems doubtful that the Keystone vote would actually help Landrieu save her seat. Polls have found Cassidy with a fairly strong margin over Landrieu. Even some of her Democratic colleagues don't seem very enthusiastic about her chances, as a Bloomberg analysis of runoff television advertisements would attest.

"I think it's too little, too late in this particular case," Pearson Cross, an associate professor of political science at the University of Louisiana at Lafayette, told The Huffington Post. Cross said the vote could have helped Landrieu more if it had come before the campaign. "If it had happened in the summer, it would have been important for her campaign to say, 'I was the person who brought this to the majority leader's attention and got it to the floor,'" said Cross. "Doing it now seems like a ploy to bolster her chance of hanging onto the seat."

Robert Mann, a journalism professor at Louisiana State University and a political columnist for the New Orleans-Times Picayune, also suggested the vote isn't going to register with voters. "You know, I have never thought that Keystone was an issue that anyone in the general population gave a flip about," said Mann. "The only time anybody talks to me about Keystone is someone from Washington calling. Real people down here couldn't care less."

Mann noted that the bill, for Landrieu, was perhaps more about distancing herself from Obama. "Unfortunately, she's standing up to the president over an issue no one cares about," he said.

This article was updated on Nov. 14 to include a Energy & Environment's confirmation of Bennet's yes vote.