"Republicans will continue to stand up for the American people and for the priorities they voted for today, and we are hopeful that the administration and Democrat leaders will change course," Republican Senate leader Mitch McConnell said in a written statement.
Democrats averted deeper losses when Gov. Joe Manchin won in West Virginia — after pointedly distancing himself from Obama — for the unexpired portion of the late Sen. Robert C. Byrd's term, and Attorney General Richard Blumenthal was victorious in Connecticut, dispatching Linda McMahon, former CEO of World Wrestling Entertainment. Sen. Barbara Boxer was elected to a fourth term in California, overcoming a challenge from Carly Fiorina.
The GOP gubernatorial gains came after a campaign in which their party organization spent more than $100 million, nearly double what Democrats had.
Among the incumbents who fell were Ted Strickland in Ohio, defeated by former Rep. John Kasich, and Chet Culver in Iowa, loser to former Gov. Terry Branstad.
In California, former Gov. Edmund G. Brown Jr. was elected to the office he held for two terms more than a quarter-century ago.
In a footnote to the brutal politics of the campaign, Republican-turned- independent Lincoln Chafee was elected governor of Rhode Island. Obama campaigned in the state in the campaign's final week. But he declined to endorse the Democratic candidate, Frank Caprio, out of what the White House said was respect for Chafee, who had endorsed the president in his own presidential race two years ago.