In Indiana, according to ABC News projections, Tea Party favorite Dan Coats will defeat Democrat Rep. Brad Ellsworth in a race to replace retiring Democratic Sen. Evan Bayh, and incumbent Sen. Jim DeMint will win another term in South Carolina.
"Tonight, there's a Tea Party tidal wave and we're sending a message to" lawmakers in Washington," Paul said in his victory speech. "It's a message on fiscal sanity, it's a message on limited constitutional government and balanced budgets."
Two of the most high-profile races of the election season, however, appeared to be less favorable for the Tea Party. GOP Delaware candidate Christine O' Donnell, who received the most news coverage of the 2010 candidates, will lose to Democrat Chris Coons, ABC News projections show.
In New York, another controversial race dominated by scandals, Tea Party-backed Carl Paladino is also projected to lose to Democratic Attorney General Andrew Cuomo.
Democrats gained a key victory in West Virginia, where Gov. Joe Manchin is projected to win, and in Connecticut, where Richard Blumenthal is projected to defeat World Wrestling Entertainment's Linda McMahon. While 88 percent were worried about the economy in Connecticut, they didn't take it out on the Democrat as voters did elsewhere; he won these voters by 54 to 45 percent.
In a victorious statement, minority Senate leader Mitch McConnell painted tonight's results as a referendum on President Obama's agenda.
"Americans have been speaking out for two years to cut wasteful Washington spending, reduce the size and scope of the federal bureaucracy, and help create sustainable, private-sector jobs," he said. "While Democrats in Washington too often acted as if they didn't hear the message, tonight the voters ensured their message was heard loud and clear."
Preliminary exit polls show strong discontent against Obama in red states and even a surprising number in his home state of Illinois, where 48 percent disapprove of the president's performance, compared with 51 percent who approve of him. Voters have been hard hit by the economy, with four in 10 saying someone in their household has lost a job or been laid off in the past two years, higher than the three in 10 nationally who say the same.
Obama carried Colorado with 53 percent of the vote in 2008; fewer of voters now, 47 percent, approve of the job he is doing as president.
Older voters have voted for the Democratic candidate in each of the past three Senate races, including voting for Feingold in 2004 by a 14-point margin, but not this time. Those age 65 and older went for Johnson, 54-46 percent.
In Kentucky, 52 percent of voters said Paul's views were too extreme but the libertarian-leaning ophthalmologist won on the back of strong anti-President Obama sentiment in the state. By a 23-point margin, voters there said they were casting their ballots in opposition to Obama, with 62 percent disapproving of Obama's job performance overall, according to ABC News exit polls.
The sentiment was similar in West Virginia, which has voted Republican in the last three presidential elections. Seven in 10 disapprove of Obama's job performance, with approval at 30 percent. Nearly half of West Virginia voters said their vote was to express opposition to Obama, while far fewer -- 14 percent -- said they voted to express support for the president.