By Jonathan Kaminsky
NEW ORLEANS (Reuters) - A push by U.S. Senator Mary Landrieu to pass a bill authorizing the contentious Keystone XL pipeline is unlikely to give the Louisiana Democrat a significant boost against her Republican challenger in a December runoff, political analysts said on Thursday.
Landrieu, who faces an uphill battle to win a fourth term against Republican congressman Bill Cassidy, is renewing efforts to pass the measure unpopular with many Democrats as she fights to retain her seat in a state increasingly inhospitable to her party.
"It's really too little, too late," said G. Pearson Cross, a University of Louisiana at Lafayette political scientist. "Doing this only when her job is in peril will be seen as not significant - or desperate."
Landrieu finished one point ahead of Cassidy in the Nov. 4 open primary, with Tea Party-backed Republican Rob Maness, who won 14 percent, having since backed Cassidy for the Dec. 6 runoff.
With Republicans set to take control of the Senate in January after gains in the midterm elections, Landrieu will relinquish her post as chairwoman of the Senate Energy and Natural Resources Committee regardless of her re-election.
But having made her clout and support for the oil and gas industry key to her campaign, Landrieu is banking on showcasing her ability to secure a vote on the bill approving the TransCanada Corp <TRP.TO> project delivering Canadian oil sands crude to the U.S. Gulf Coast.
"She's been beating this drum, but she couldn't get leadership to allow a vote," said Dane Strother, a Democratic media consultant. "Now there's an opening and now she'll get it done."
Her late push on the pipeline, however, risks backfiring, said John Couvillon, a Louisiana pollster working mostly for Republicans.
"She is implicitly admitting that she had no clout because she couldn't get this passed earlier," he said.
The impact of Landrieu's Keystone push on the runoff is also blunted by Cassidy having responded to her announcement by immediately introducing a nearly identical bill in the Republican-controlled House, analysts said.
"Cassidy is going to be able to easily neutralize this by saying it took her six years to do this," said Joshua Stockley, a political scientist at the University of Louisiana at Monroe. "And he is going to get the same vote in the House."
Representatives for Landrieu and Cassidy did not immediately respond to messages seeking comment.
(Reporting by Jonathan Kaminsky; Editing by Eric Beech)