Keystone XL: Can a pipeline rescue Democrats" Louisiana Senate seat? Even if Sen. Mary Landrieu (D) of Louisiana loses her December runoff election, she may leave a parting gift on President Obama's desk: a bill to approve the Keystone XL pipeline. In the week since Republicans captured the Senate, Senator Landrieu is the only vulnerable Democrat whose fate remains in the air. The three-term senator is headed to a Dec. 6 runoff against Rep. Bill Cassidy (R) after neither garnered more than 50 percent on Election Day. To score a win before the runoff and boost her chances, Landrieu took to the Senate floor Wednesday to push for a vote on the long-delayed Keystone XL pipeline. Minutes after Landrieu called for a vote, Representative Cassidy tried to undercut her efforts by introducing an identical bill in the House. "It is easy to wonder if the Senate is only considering this because of politics," Cassidy said Wednesday on the House floor. Even so, I hope the Senate and the president do the right thing and pass this legislation creating thousands of jobs. A House vote is set for Thursday. But even if there's a vote in the Senate, it's not clear the move will help Landrieu, who has trailed Cassidy in the polls. "I'm not sure it will persuade enough voters," says Brian Brox, a political science professor at Tulane University in New Orleans. Landrieu's key to victory is an outstanding turnout among African-Americans. Keystone really isn't going to affect their vote. If built, the Keystone XL pipeline would transport around 800,000 barrels of Alberta tar sands (also known as oil sands) per day from Canada to US Gulf Coast refineries. That's almost as much oil as North Dakota - the US state with the second-highest output - produces per day. Oil prices globally have dropped about 30 percent since they began a downward slide in June. And with oil prices hovering at $80 a barrel, Keystone XL and the expensive, difficult-to-extract Alberta tar sands it would carry are looking riskier - regardless of what the Senate decides. "[I]t will be one of the early victims of a low-price economy," says Stuart Page, chief executive officer at Glori Energy, an oil recovery company in Houston. But these are long-term capital investments, and you don't turn them off on a dime. Eventually, oil prices are likely to rebound, making tar sands more profitable. Still, environmentalists say approving Keystone XL would only encourage further long-term investment in carbon-intensive tar sands. "We're seeing this play out politically, despite the fact that dramatic changes in the market in recent months have undermined the case for Keystone XL," says Anthony Swift, a staff attorney at the Natural Resources Defense Council, an environmental nonprofit. Even before the rapid decline in oil prices, tar sands projects were on the edge of economic viability. Cassidy is the favorite in red-leaning Louisiana, despite the clout Landrieu has as a high-ranking member of the Energy Committee - an important post in oil-rich Louisiana. Incoming Majority Leader Mitch McConnell has promised that if Cassidy wins, he'll get a spot on the Energy Committee. GOP leaders have also promised a vote on Keystone XL as soon as they take over the upper chamber in January, and they likely have enough votes to approve the pipeline. The bill would still require presidential approval, and Press Secretary Josh Earnest said Nov. 6 that Obama would consider signing it. Before Election Day, Landrieu listed President Obama's hesitance on Keystone as one of the factors making her reelection bid so difficult. "One of the main reasons is because his energy policies are really different than ours," Landrieu said on NBC's "Meet the Press" prior to Election Day.