WASHINGTON - (AP) - Democrats retained their Senate majorityTuesday, losing six seats but winning key races in Nevada, WestVirginia and California.

Republicans scored impressive gains, taking Senate seats fromDemocrats in Pennsylvania, Wisconsin, Arkansas, North Dakota andIndiana. They even won the seat in Illinois that had been held byPresident Barack Obama before his election in 2008.

But the net gain of 10 they needed for control of the upperlegislative chamber eluded them.

In the lower House, Republicans regained the majority they lastheld in 2006.

With Republicans in control of the House, Obama will need aDemocratic-run Senate to champion his legislative agenda and gethis nominees approved.

Veteran Democratic Sens. Russell Feingold of Wisconsin andBlanche Lincoln of Arkansas lost re-election bids.

But West Virginia Gov. Joe Manchin held off millionaireRepublican John Raese to keep a Democrat in the seat held for halfa century by the late Robert C. Byrd. And Democratic Sen. BarbaraBoxer of California won a fourth term despite a spirited challengefrom Republican Carly Fiorina.

Republicans also failed to oust Senate Majority Leader HarryReid in Nevada. The Democratic leader - a leading Obama supporter -seized a fifth term after a vicious battle with tea party starSharron Angle.

Those victories left Republicans no way to take the majority.They could still possibly achieve a 50-50 split. But Vice PresidentJoe Biden, the Senate's official president, would break ties in theDemocrats' favor.

Tea party champions won high-profile races in Florida andKentucky, spearheading a likely cadre of libertarian-leaningRepublicans who will press party leaders to be more adamant aboutlower taxes and less government spending.

Connecticut Vote 2010 Complete Coverage