Polls conducted after Maryland's Democratic primary in September had given Cardin a double-digit lead over Steele, the state's lieutenant governor.

In a strongly Democratic state and in a national anti-GOP climate, Steele marketed himself as the anti-establishment candidate, with ads that attacked both parties and campaign signs and materials printed in bright blue, the traditional color of Democrats. "Steele has made it more of a race than you would think, given how blue the state is and how thin his record is," says University of Maryland-Baltimore County political scientist Tom Schaller. "He needed to run an image-oriented, issue-less campaign that said 'I'm a change agent,' and he did it brilliantly. He probably won the campaign but lost the election."

Cardin, a policy wonk often described as "charismatically challenged," has built his campaign around lashing Steele to the White House, which recruited Steele to run, and at highlighting Cardin's vote in the House against authorizing the Iraq war. The first African-American to have been elected to statewide office in Maryland, Steele has made a strong pitch to black voters, who account for nearly 30 percent of the electorate and who traditionally support Democrats by margins of 90 percent. A handful of current and former officials in Steele's native Prince George's County, a mostly African-American enclave outside Washington, D.C., last week crossed party lines to endorse Steele. But the University of Maryland's Schaller says that the Democratic Party's neglect of African-American Marylanders is a storyline fueled mostly by the Steele campaign. He says Steele would likely need to win more than a quarter of the black vote to win tomorrow, which he considers unlikely.

—Dan Gilgoff