In a rebuke to one of their endangered colleagues, Senate Democrats blocked a bill to jump start construction of the Keystone XL oil pipeline from Canada by a single vote, as Republicans immediately vowed to bring the plan up next year, when they will control both houses of Congress.

"It is so clear to the people of Louisiana that this pipeline should be built," said Sen. Mary Landrieu (D-LA), who used the debate to try to infuse some momentum in her re-election campaign, now headed to a December runoff against Rep. Bill Cassidy (R-LA).

"Enough is enough," said Landrieu about delays in final approval of the pipeline.

But only 13 other Democrats voted with Landrieu, leaving her one vote short of the 60 needed to advance the measure, as Landrieu was done in by members of her own party who hotly oppose the Keystone project.

"What we're talking about here is the dirtiest, filthiest oil on the planet," said Sen. Barbara Boxer (D-CA).

"We know misery follows this pipeline," Boxer said before the vote.

"There's real harm that this will cause," said Sen. Sheldon Whitehouse (D-RI), who says bringing in this oil from Canada would undermine action by the Obama Administration on climate change.

Liberal groups had turned up the heat on Democrats in recent days, demonstrating in front of Landrieu's home on Capitol Hill, and sending out fundraising letters calling for the defeat of the Keystone pipeline.

"Today's Senate vote could be 'game over for the planet,'" read an email from the group MoveOn dot org.

But the Democratic Party coalition did not stay together fully on the Keystone issue, as a major construction union absolutely savaged Democrats in a post-vote news release.

"As the White House politicized the construction of the pipeline, 41 Senate Democrats cowardly stepped in line, throwing one of their own colleagues, Sen. Mary Landrieu, along with hard working blue-collar construction workers under the bus," the union said in a written statement.

The result had the union allied much more with Republicans, as GOP lawmakers contend the immediate construction of the pipeline would only be good for U.S. economic growth.

"This will generate 42,000 jobs," said Sen. Johnny Isakson (R-GA). "That's a lot of jobs."

"We know that the Keystone XL pipeline would be good for our economy," added Sen. John Cornyn (R-TX).

The bill's rejection means that no veto will be needed now by President Obama - but that could certainly change in the 114th Congress, when Republicans will control both the House and Senate.

If votes from today hold in 2015, then Republicans should have more than 60 votes - with the help of some Democrats - to move the Keystone XL bill.

But a veto would seem to await in the new year.

The full Senate vote is available on the U.S. Senate website.