US Senator Mary Landrieu, one of the last standing elected Deep South Democrats, lost her bid Saturday for re-election in Louisiana, further clinching Republicans' dominance in the Senate following mid-term elections last month.

   Her loss to Republican rival Bill Cassidy in the runoff vote consolidates a conservative majority in the southern state, in a region where political winds have shifted strongly in the Republicans' favor in recent years.

   The vote -- the last in the Senate contest and the only runoff -- comes after Democrats suffered a sweeping blow in November 4 legislative elections, which saw energized Republicans reclaim the Senate majority and expand their control in the House of Representatives.

   Republicans will hold 54 out of 100 seats in the Senate next year, nine more than they hold today.

   Landrieu, who was elected in 1997, said she had no regrets and applauded the work of her party in dealing with various catastrophes, including several hurricanes that battered Louisiana during her tenure.

   "Tonight, we have so much to be proud of, a record of courage, honesty and integrity and delivering for the state when it mattered the most in some of our darkest hours after Katrina, Rita, Gustav, Ike, and the BP oil spill," she said in New Orleans after her defeat.

   "The joy has been in the fight, it's been a blessing, it's been a fight worth waging. Louisiana will always be worth fighting for."

   According to final official tallies, Cassidy took about 56 percent of the ballot.

   The Republican National Committee applauded Cassidy's win, and congratulated voters for making the right decision. 

   "Once again, voters have spoken clearly. They have rejected the Democrat agenda and the Obama-Clinton policies that have produced higher health care costs and job-killing regulations," RNC Chairman Reince Priebus said in a statement, referring to President Barack Obama and former US Democratic president Bill Clinton. 


   - Pipeline politics -

   In a state inextricably tied to the oil and gas industry, Landrieu had played up her importance for constituents as chair of the Senate Energy Committee.

   But her recent push to get the Senate to approve construction of the Keystone XL pipeline, a project popular with Republicans, ended disastrously when she fell one vote short.

   The RNC said building the pipeline would be a major priority for Cassidy.

   "Bill Cassidy will be a champion for policies that create jobs and grow the economy, especially building the Keystone Pipeline," Priebus said.

   Landrieu's appeal for support from her Democratic base was not enough to secure her win in Louisiana, which is majority African American and where her brother is mayor of New Orleans, the state's largest city.

   Obama's waning popularity further weakened her bid for re-election in a region that has seen a rise in Republican support.

   Analysts had predicted turnout for the runoff to be whiter, older and more Republican than in presidential election years.

   Experts suggest the Democratic Party is already shifting its focus -- and funding -- to the 2016 presidential and congressional races. (AFP)