—Mark Warner, Virginia. After getting a law degree from Harvard, Warner, now 54, moved to Washington, where he earned as little as $350 a week as a Democratic fundraiser. He turned to business, making millions by obtaining licenses to radio frequencies that would one day link millions of wireless telephones. In 1996 he spent $10 million of his own money in a close but unsuccessful attempt to unseat GOP Sen. John Warner (no relation). He was elected Virginia governor in 2001 and explored but later abandoned seeking the Democratic presidential nomination in 2008.

Republicans (2):

—Mike Johanns, Nebraska. Johanns, 58, comes to the Senate with a wealth of government service. Switching from Democrat to Republican and entering local politics in 1983, he was mayor of Lincoln from 1991 to 1998, served as governor from 1999 to 2005 and was the Bush administration's Agriculture secretary from 2005 to 2007. He succeeds Republican Chuck Hagel, who retired.

—Jim Risch, Idaho. Risch, 65, succeeds Larry Craig as Idaho's Republican senator. Like other Western Republicans, he is a fiscal conservative who supports gun rights, opposes giving amnesty to illegal immigrants and supports greater development of U.S. energy resources. He won his first election, as a local chief prosecutor, at age 27. That was the first of 31 campaigns that would eventually make Risch a state senator, two-time lieutenant governor and governor before his election to the Senate.