In Massachusetts, Democrat Elizabeth Warren defeated Sen. Scott Brown, to become the first female senator in the state’s history. Brown won the seat in a 2010 special election to fill the seat of the late Sen. Ted Kennedy.
Warren, a Harvard law professor, chaired the Congressional Oversight Panel for the Troubled Assets Relief Program, and helped craft the Wall Street reform legislation known as the Dodd-Frank bill. Last year, Warren made news for giving her own version of “you didn’t build that,” when speaking at a campaign event.
“There is nobody in this country who got rich on his own,” Warren said in August 2011. “You built a factory out there? Good for you. But I want to be clear: you moved your goods to market on the roads the rest of us paid for; you hired workers the rest of us paid to educate; you were safe in your factory because of police forces and fire forces that the rest of us paid for. You didn't have to worry that marauding bands would come and seize everything at your factory, and hire someone to protect against this, because of the work the rest of us did.”
In her victory speech, Warren told her supporters, "This victory belongs to you. You did this!" She also promised to live up to the promises made by the late Sen. Ted Kennedy.
In another significant Democratic pickup, Indiana Democrat Rep. Joe Donnelly defeated Republican state Treasurer Richard Mourdock, who made headlines when he said that pregnancy resulting from rape is “something God intended.” The seat has been in Republican hands since 1976, when Sen. Richard Lugar won it. But Mourdock defeated Lugar in the May Republican primary.
In a contest that turned largely on a gaffe, Sen. Claire McCaskill won reelection, defeating Republican Rep. Todd Akin in Missouri. McCaskill was seen as vulnerable in a state that the GOP presidential candidate carried handily. However, in August, in an interview with a St. Louis TV station, Akin – responding to a question about abortion – said, “If it’s a legitimate rape, the female body has ways to try to shut that whole thing (pregnancy) down.” Despite apologizing and clarifying his comment, Akin was not able to recover.
In a bit of a surprise in Wisconsin, Rep. Tammy Baldwin defeated former Republican Gov. Tommy Thompson. Thompson also served as the secretary of Health and Human Services under the George W. Bush administration. The seat is held by retiring Democratic Sen. Herb Kohl.
In another closely watched race to fill the seat of the retiring Independent Sen. Joe Lieberman in Connecticut, Rep. Chris Murphy defeated pro wrestling executive Linda McMahon, the Republican candidate. This is the second time McMahon has run for a Senate seat. Liebermann, the 2000 Democratic vice presidential nominee, became an independent after losing a Democratic primary in 2006. But he continued to caucus with Democrats.
In a closely contested battle of former Virginia governors, former Democratic National Committee Chairman Tim Kaine defeated Republican George Allen. Allen lost the Senate seat in 2006 to James Webb, who did not seek reelection this year.
It wasn’t all bad news for Republicans, as Nebraska state legislator Deb Fischer defeated former Nebraska Governor and Senator Bob Kerry in a closely watched race.
Senate Democrats began Wednesday with 52 seats to the GOP’s 44, with three races still undecided and Maine’s newly elected independent, Angus King, saying he hasn’t decided which party he will align with.
Senate Majority Leader Harry Reid ( D-Nev.) said Republicans brought defeat on themselves by trying so hard to deny President Barack Obama a second term.
"Things like this are what happens when your No. 1 goal is to defeat the president and not work to get legislation passed," Reid said. "The strategy of obstruction, gridlock and delay was soundly rejected by the American people. Now they are looking to us for solutions," he said in a separate statement.
The Senate has not passed a budget in three years.
Senate Minority Leader Mitch McConnell ( R-Ky.) said the voters have not endorsed the "failures or excesses of the president's first term," but rather have given him more time to finish the job.
"To the extent he wants to move to the political center, which is where the work gets done in a divided government, we'll be there to meet him half way," McConnell said.
In a statement, Sen. John Cornyn (R-Texas), chairman of the National Republican Senatorial Committee, said the GOP has work to do.
"We have a period of reflection and recalibration ahead for the Republican Party. While some will want to blame one wing of the party over the other, the reality is candidates from all corners of our GOP lost tonight," Cornyn said, though he added that the party's "conservative vision is the right one to secure a stronger America for future generations."
(The Associated Press contributed some of the information in this report.)