On Meet the Press yesterday, Charlie Crist said that he is open to caucusing with the Democrats if he's elected to the Senate:
"I'm going to vote for who I think is going to be best for the people of Florida. If is happens to be a Democrat, so be it. If it happens to be a Republican, so be it."
Consider the ways that Charlie Crist's independent bid might work out, and in each scenario it seems most likely that he will become a Democrat.
Scenario 1: Crist wins. The most plausible path to victory for Crist is if he pulls into second place behind Rubio in the polls, and cuts a deal with national Democrats: Crist will caucus with them if they back him and push Meek out of the race. In the even more unlikely event that Crist wins without any such deal, the Democrats will still likely have the majority in the Senate, and Crist won't want to caucus with minority Republicans who view him as a pariah.
Scenario 2: Crist loses. What does Crist do if his poll numbers drop into the low twenties or teens? If he still wants a career in politics, it would be in his self-interest to throw his support to Meek. And if there's one guiding principle to Charlie Crist's politics, it's self-interest over all. With his career over in the Republican party, backing Meek would open the door to Crist running as a Democrat in the future (though you'd think the experience of Arlen Specter would counsel against this option) or, at the very least, securing a job from the Obama administration.