WASHINGTON — The Senate stopped just short of approving the long-delayed and controversial Keystone XL pipeline Tuesday night. The 59-to-41 vote, with 14 Democrats joining all 45 Republicans in favor of approving the Keystone XL measure, was just shy of the 60 votes needed for the legislation to advance.

The harrowingly close results spare President Barack Obama from having to choose whether or not to issue a veto on Keystone XL, which has proven a divisive and polarizing issue for the duration of his administration, pitting environmental concerns against the initiative's job-creation potential.

After stalling and skirting the issue for years, Majority Leader Harry Reid chose to at last schedule a vote on the project in the lame duck session, ostensibly to help embattled Louisiana Sen. Mary Landrieu, a fellow Democrat, secure re-election. After garnering less than 50 percent of the vote on election night, Landrieu will face Republican opponent Rep. Bill Cassidy, R-La. in a Dec. 6 runoff vote, in which her chances of holding her seat are looking increasingly slim.

Her inability to corral enough Democratic votes to pass the legislation will undoubtedly deal another blow to her push for a fourth term.

After the vote, Landrieu vowed in a press conference to keep working “until the day that I leave.”

“I hope that is not soon,” she said.

The Republican-controlled House already voted last week to give the pipeline the go-ahead, 252-161, with Cassidy sponsoring the legislation in the lower chamber.

Both candidates hoped that helping to orchestrate the pipeline’s approval and burnishing their energy credentials would give them an edge among voters in Louisiana, a state where the gas and oil industry is powerful.

Landrieu hammered home her arguments in favor of the project as she spoke on the Senate floor Tuesday night, appealing to fellow Democrats to get to the 60-vote threshold. She said that moving forward with Keystone XL’s construction would “send hope to the middle class” by creating jobs and developing the United States’ energy infrastructure.

“This resource will be produced,” she said. “Nothing that we do on this floor, what they do in the House, or the president of the United States does will stop this resource from being produced.”

The White House has delayed a decision on the pipeline for years, with officials saying they are awaiting a final State Department environmental impact review of the project, taking into account a forthcoming Nebraska Supreme Court decision that may alter the pipeline’s planned route.

“Understand what this project is — it is providing the ability of Canada to pump their oil, send it through our land, down to the Gulf, where it will be sold everywhere else. That doesn’t have an impact on U.S. gas prices,” Obama said last week while on a visit to Myanmar. “You know what does have an impact on U.S. gas prices is the incredible boom in U.S. oil production and natural gas production that’s taken place under my administration.”

Republicans, meanwhile, spent Tuesday evening’s floor debate assailing the president for punting on the decision.

“The American people want it and he won’t approve it,” said Republican Sen. John Hoeven of North Dakota, a co-sponsor of the legislation. “His strategy is defeat through delay, defeat through delay.”

Even with Tuesday night’s results, it is very likely the president will have to deal with the issue again when the new Republican Senate majority takes power in January. Sen. Mitch McConnell, who will then take over as majority leader, and House Speaker John Boehner have said approval of Keystone XL is one of their key priorities.

“Once the 114th Congress convenes, the Senate will act again on this important legislation, and I look forward to the new Republican majority taking up and passing the Keystone jobs bill early in the New Year,” McConnell said in a statement after the vote.

The pipeline’s backers say its construction would create tens of thousands of American jobs — albeit temporary — and generate approximately $2 billion of economic output, according to an earlier State Department review completed in January. Environmentalists, however, stridently oppose the pipeline’s construction, saying it would signal a continuing commitment to fossil fuels as the U.S. should be transitioning to cleaner forms of energy that do not contribute to climate change. Some ranchers and Native Americans also object to the pipeline being built across their lands.

“If we want to grow this energy economy with good jobs, we want to protect our families' health, we want to protect our planet from devastating climate change, the vote is no on the Keystone XL pipeline,” said Sen. Barbara Boxer, D-Calif. on the floor. “We know misery follows the pipeline.”

The January State Department assessment also found that Keystone XL would not have a significant impact on greenhouse gas emissions because the oil will be produced anyway, even without the pipeline to transport it.