Tampa, Fla.

Until now the best roles in Florida's Senate election drama were taken by Republicans. The tea party upstart, Marco Rubio, forced Gov. Charlie Crist to drop his lagging primary bid and take his chances as an independent. But now the Democratic script turns out to be as unpredictably wacky.

Enter Kendrick Meek, stage left. A young and popular African-American congressman from Miami, the former state trooper got into this campaign before anyone else and expected a smooth ride to the Democratic nomination. The subsequent GOP civil war seemed to give him a leg up.

Kendrick Meek (left) and Charlie Crist are both vying for Florida's Senate seat. Associated Press

The downside of running as the establishment candidate eventually became clear. He can't run away from his association with the Obama agenda, and he can't escape whispers that the White House might hedge its bets and tacitly back Mr. Crist. Two months before the Aug. 24 primary, Mr. Meek doesn't have traction in the polls, which show a double-digit gap against Mr. Rubio and Mr. Crist. And seven weeks ago the proverbial man from nowhere—billionaire investor Jeff Greene—decided to challenge Mr. Meek for the Democratic nomination.

When I meet him on muggy evening last week, after campaign stops in Orlando and Sarasota, Mr. Meek puts on shorts, grabs a beer and fishing rod, and drops a line into Tampa Bay. He is an avid fisherman and hunter, unusual interests for a congressman who represents inner city Miami, and he uses them to reach out to white, non-urban voters. Nothing bites—until half an hour in, when a catfish comes up. "That's how it happens in fishing: Just when you least expect it," he says.

Mr. Greene was also unexpected. At first blush, he carries a lot of baggage. He lived the high-life in California, befriending Mike Tyson (the best man at his 2007 wedding) and Hollywood Madam Heidi Fleiss, who lived at his house for a year. Now 55, Mr. Greene doubled his net worth in recent years by betting against the subprime mortgage market.

"Nobody cares about all this," he insists in a conversation last week after appearing before the Florida Press Association in Sarasota. When he announced his candidacy, Mr. Greene declared that "I'm just as frustrated as you are" with Washington. A flurry of television ads later, Mr. Greene polls neck-and-neck with Mr. Meek. Apparently the professional politician slur works as well with Democrats as Republicans.

"Kendrick Meek is unelectable," Mr. Greene says, noting that with "a lot of the demographics, I will do much better than Kendrick Meek." By implication, that means nonblack voters in central Florida and the panhandle, where Mr. Meek polls badly. "He's been running for a year and a half," Mr. Greene adds. "He's been in Congress for eight years. I've been in six weeks and I'm even with him already. Doesn't that tell you something?"

Read more about this race:

Political Diary: Florida Dems in Disarray

Later that day, Mr. Meek seizes on his opponent's allusion to race. "If I'm demographically challenged, I wonder what his challenges are," he tells me, going on to answer his rhetorical question. Mr. Greene is a "carpet-bagger," having moved to the state only two years ago; he's a closet Republican who has rarely voted; his multimillion-dollar trades in credit default swaps profited "off the backs of Floridians" who defaulted on their homes; he's a man out "to buy Florida's Senate seat."

In a year of anti-incumbent fervor, these charges aren't sticking. Mr. Meek optimistically claims that the harder primary fight will help raise his profile before November, and that he hasn't yet countered with a large TV push. But the congressman also faces the challenge of his own record. He voted in party lockstep, backing ObamaCare and the stimulus. Yet when asked if he can win defending the president's agenda, he immediately shoots back that, "I'm not running on the Obama agenda. I'm running on the Florida agenda."

The candidate triangulates with unexpected dexterity for a former standout defensive lineman at Florida A&M. Mr. Meek tries to distance himself from the White House without disavowing his votes. So he says he isn't "prepared to support a second stimulus right now" and backs "fix-it bills" to improve ObamaCare in the future. In public appearances, the name Barack Obama is notable by its absence.

So far the White House has returned the favor to Mr. Meek, keeping its distance. The race is one of the best opportunities to flip a Republican Senate seat blue in 2010—or at least neutral with Mr. Crist, who hasn't said which party he would caucus with in the Senate. If Mr. Meek can't make up the gap in polls, goes the thinking, the president won't throw his weight behind him and eat into Mr. Crist's support.

Mr. Meek sounds confident that President Obama won't dare abandon him and risk angering his allies in the Congressional Black Caucus. "When Air Force One lands," he says, "it'll be landing for me and not for Charlie Crist or anyone else." But publicly, the current occupant of the White House may not be the president this candidate wants at his side. More than once, Mr. Meek notes the support of Bill Clinton. In this cycle, the former president has proved a better asset on the Democratic campaign trail than Mr. Obama.

For all his troubles, in this goofy year Mr. Meek puts forward a credible scenario for victory. In a three-way race he could conceivably win with a plurality of 34%, taking advantage of the Democrats' sizable lead in party registration. But first this lukewarm but establishment Obama Democrat must secure a ballot spot in November.

Mr. Kaminski is a member of the Journal's editorial board.