Voters in Florida—one of five states (the others are Alaska, Arizona, Oklahoma and Vermont) holding primary or runoff elections Tuesday—are about to decide one of the fiercest Democratic US Senate primaries of a year packed with intense inside-the-party contests.

And, as in Arkansas and Colorado, Bill Clinton could turn out to be a definitional player.

Clinton’s campaigning for Arkansas Senator Blanche Lincoln played a critical role in her run-off victory over challenger Bill Halter in a June 8 run-off election.

Clinton’s campaigning for progressive Andrew Romanoff helped the challenger to come within a hair of upsetting appointed incumbent (and Obama administration favorite) Michael Bennet in that state’s August 10 Democratic primary.

Now, Clinton is getting credit for helping to resurrect the candidacy of Congressman Kendrick Meek, who gave up his safe seat to bid for the Democratic Senate nod. Meek was the presumed nominee for months, but then he got hit with a free-spending challenge from real-estate billionaire Jeff Greene, who made his money by buying credit default swaps that rose in value when subprime borrowers defaulted on their home loans. The "meltdown mogul"—as Meek dubbed him—pumped roughly $25 million into television and radio ads and mailings to likely primary voters. Not surprisingly, he surged in the polls.

Greene’s spending overwhelmed Meek and it appeared that another wealthy newcomer—like California Republican gubernatorial nominee Meg Whitman, California Republican Senate nominee Carly Fiorina and Connecticut Republican Senate nominee Linda McMahon—might beat a buy a nomination that had been expected to go to a candidate with more experience but less money.

When Meek was at his weakest point, however, Clinton stepped in to campaign for the congressman, stumping in a state where the former president remains extremely popular with Democratic voters.

Then came a series of revelations about wild parties on Greene’s former home in Los Angeles—complete with appearances by boxer Mike Tyson and Hollywood madam Heidi Fleiss—and intoxicated romps aboard the billionaire’s private yacht.

The combination of Clinton’s campaigning—the ex-president attended five fundraisers for the congressman, sent two fundraising e-mails on his behalf, and then appeared at rallies in Palm Beach, Broward and Miami-Dade counties—and the sin-at-sea stories swirling around Greene shifted the dynamic of the race at the close.

But Greene was still attacking Meek as the primary approached, and the polls were unsteady enough, that Clinton stepped up once more—recording a robo-call that had the former president greeting Florida Democrats with the following message:

"Hi, this is President Bill Clinton. I’m calling on behalf of Kendrick Meek. Both President Obama and I are supporting Kendrick for the US Senate, and we hope you will vote for him. He’s the Real Democrat in the race. The only one with a record of working hard to make all our lives better every day. Now it’s time to fight for him because he’s always fought for us. Early voting’s already begun and Election Day’s next Tuesday. So I’m calling to ask you to go and vote for my friend Kendrick Meek. He’ll make us all proud because he’ll make a real difference. Thank you."

If Meek wins, as now seems likely, he’ll be thanking Clinton. And a lot of other Democrats in tough races around the country will be looking for ways to get the former president to work as hard for them as he has for his candidate in Florida.