Challenger Rep. Bill Cassidy(R) ousted Landrieu by a 56% to 44% vote margin in a run-off election.
Landrieu had trailed Cassidy significantly in recent polls and the Democrat campaigning machine had largely abandoned her despite her 34 year tenure as Senator.
Landrieu had been touting her seniority in the Senate as a benefit to the state of Louisiana. She had managed to get a floor vote on the Keystone XL pipeline but was unable to muster the one additional democrat vote needed to get it passed.
The democrat loss in Louisiana finishes a long string of losses for liberals in the senate during the 2014 mid-term elections.