Mid-term elections are often viewed as a barometer of public mood - and as a referendum on the political party in office. There are conflicting analyses of Tuesday night's victories and losses, though.
New York elected its first Democratic mayor in 20 years. Bill de Blasio will be the Big Apple's next mayor.
Conservative Republican Ken Cuccinelli lost the race for Virginia governor to Democrat Terry McAuliffe.
"This race came down to the wire because of Obamacare," he said.
"It made the race closer than it was going to be. McAuliffe was expected to win by a wider margin - he won by two and a half points," said Prof. Larry Sabato, University of Virginia Political Analyst.
The moderate Republican Chris Christie won re-election in New Jersey - with a majority of women, Latinos, a third of Democrats and one out of five African-Americans voting for him.
"Maybe the folks in Washington, DC should tune in their TVs right now and see how it's done," said Gov. Christie.
Republicans are hailing the victory as a means to win in states that trend "blue," but some Democratic commentators point out that Christie's win could be as much about voters rejecting a Tea Party candidate as it is about embracing a moderate Republican.
As the president heads to Dallas Wednesday to push his health plan, the electorate is pushing politics to the middle. But health care remains a central issue.
Health and Human Services Secretary Kathleen Sebelius testified again Wednesday about the government's troubled website.
"The American people do not like Obamacare," said Sen. Mitch McConnell (R-KY).
The White House is on the defense as millions of Americans get letters canceling their coverage.
"Those letters are only being sent to a fraction, a very small fraction of the population," said Jay Carney, White House Press Secretary.
The exit polls showed New Jersey's popular Republican governor could not beat Hillary Clinton there in 2016.