But with polls too close to call in Montana and Virginia, a Democratic Senate majority will remain undetermined for at least 10 more days.

Democrats carried 49 seats, and Republicans hold 49.

Democrats are expected to win in Montana. With 74 percent of the precincts reporting, Jon Tester led with 50 percent of the vote against the incumbent Conrad Burns.

In Virginia, incumbent Republican Senator Jim Allen, once a 2008 presidential hopeful, began to lose his stronghold to Democratic challenger Jim Webb when he called a Webb volunteer of Indian decent “macaca.”

Webb currently holds an 8,000-vote lead, a number small enough to warrant a recount. Though the informal winner will be announced soon, the results won’t be certified until Nov. 27.

Despite winning a majority in the House, the lack of a Senate majority will limit the Democrats ability to shift power away from the Bush administration.

"If there is a President George W. Bush to veto, there isn’t very much for Democrats to do," said Robert Reich, professor of Public Policy at the Goldman School of Public Policy, UC Berkeley, and former Secretary of Labor under the Clinton Administration.

With Supreme Court Justice John Paul Stevens poised to retire, and Justice Ruth Bader Ginsberg potentially following suit, maintaining Senate control means Bush will continue to have the party votes to appoint his top choices to the Supreme Court.

Regardless, the closeness of the campaign had Democrats cheering.

Rising anti-Republican sentiment springing from the war in Iraq and recent corruption scandals played a key role in the four seats Democrats easily pulled away from Republican incumbents.

Perhaps no lost seats reflected this as clearly as that of Lincoln Chafee, one of the most liberal Republican senators, who lost his Rhode Island seat to Democratic challenger Sheldon Whitehouse.

Similarly, moderate Republican incumbent Mike DeWine of Ohio lost his seat to Democratic challenger Sherrod Brown, getting only 45 percent to Brown's 55.

“At this point, having Republican after your name is like having horns and a tail,” said Peg Rosenfield, spokesperson for the League of Women Voters of Ohio, a week before Election Day.

In Pennsylvania, Rick Santorum strayed from his party’s advice to focus on local issues, trumpeting his support for the Bush administration and asking voters to support him in confronting terrorist threats beyond Iraq. Democratic challenger Bob Casey also emphasized Santorum’s support for the president, and won 59 percent to Santorum’s 41.