It's his fall with Republicans that gets all the attention, but Charlie Crist's poll numbers have declined almost as badly with Democrats and independents over the last year as they have within his own party. And that makes me doubt he would be successful in an independent Senate bid even if he did decide to make a run for it.
Comparing Quinnipiac's April 2009 poll to its poll this month Crist's approval rating has dropped 19 points with Republicans, from 68% to 49%. But it's also dropped by 18 points with independents from 68% to 50% and by 14 points with Democrats from 66% to 52%.
Right now Crist gets 30% of the Republican vote and 27% of the Democratic vote if he runs as an independent. But it's important to keep in mind that 61% of Democrats don't know enough about Kendrick Meek to have formed an opinion of him yet- are Democrats who like Crist and don't know Meek today still going to vote for Crist this fall once they know Meek? Given the downward trend in his poll numbers among Democrats it seems like he would lose a lot of that support. The same is even true with Rubio, although to a lesser extent. 25% of Republicans still don't have an opinion about him.
The ideological war in the Republican Party is certainly a big part of Charlie Crist's trouble right now. But he's on the decline across the board and has been pretty much since he decided to run for the Senate instead of seeking reelection as Governor. I think part of Crist's problem might be a feeling from voters that he's overly ambitious- and leaving his party to try to get elected to the Senate won't do much to assuage that problem. It's too early to write the obituary on Crist's political career- too many amazing comeback stories in the annals of politics to do that- but a victory in 2010 seems unlikely under any scenario.