US Republican Louisiana victory boosts Senate majority
US Republicans have increased their majority in the Senate after a runoff from the mid-term elections ended in defeat for the Democrats in Louisiana.
Republican Bill Cassidy's win against Senator Mary Landrieu swells their ranks in the 100-seat chamber to 54.
Republicans have now gained nine Senate seats in the mid-term elections.
There was more bad news for the Democrats when Republicans kept control of two Louisiana seats in runoffs for the House of Representatives.
It means Republicans will increase their current 234-201 advantage in the House by a dozen seats in the next Congress - with one election still to be decided.
Republicans now control both chambers of Congress for the first time since 2006.
Ms Landrieu, 59, was unable to win a fourth term in the face of voter dissatisfaction with President Barack Obama, a Democrat.
She had tried to focus the election on her own performance but Mr Cassidy, 57, portrayed his candidacy as a way for voters to cast another ballot against Mr Obama's policies.
The Republicans now have the power to complicate - if not block completely - Mr Obama's agenda in the last two years of his tenure in the White House.
Control of the Senate will also enable the Republicans to impede his ability to name new federal judges, cabinet members and senior government officials.