The most surprising aspect of the poll is that more than a third of Maryland Democrats remain undecided on whom to support, roughly the same number as eight months ago. "Neither of the two candidates have done anything demonstrable to reach voters over the last six months," says Keith Haller, president of Potomac Inc., which conducted the poll. "It's been a game of endorsements, raising money, and building the campaigns behind the scenes."

The poll, released this morning, gave Cardin a clear advantage in a matchup with the likely Republican Senate nominee, Maryland Lt. Gov. Michael Steele. Cardin has a lead of 11 percentage points over Steele, while Mfume and Steele, both African-Americans, are locked in a statistical tie.

Even so, Haller says the huge chunk of undecided voters is likely to play to the advantage of Mfume, former head of the National Association for the Advancement of Colored People, because he already has sealed up a lopsided majority of the state's black vote. "From Day 1, he's had star power in the African-American community and is likely to get 85 or 90 percent of that vote," says Haller. "It's a narrow political base, but in a Democratic primary it can count for a lot."

Indeed, African-Americans account for a quarter of Maryland's population and as much as 40 percent of the state's Democratic vote. At the same time, though, Cardin has raised nearly $4 million so far, roughly six times as much as Mfume. But with a big field of second-tier candidates in the Democratic primary, including millionaire real estate developer Josh Rales, Cardin faces the danger of losing some white voters in the primary. "Everybody has been parsing the lack of progress in Mfume's campaign, the fact that he hasn't raised money and that his campaign has no structure," says Haller. "That's a false way to judge this race."–Dan Gilgoff