Via Democracy in America, a new Rasmussen poll on the Florida Senate race shows Crist with a modest four-point lead in the three-way race with Rubio and Meek. It may be that Crist’s considerable backing from Democrats (44%) and Republicans (30%) will evaporate as Meek becomes better known and Republican voters rally around their nominee after August, but unfortunately* it appears that Crist still has a significant advantage in favorability. Crist is so much more well-known than Meek that it could be Meek who loses his supporters to him.

Despite jumping ship, Crist still has 41% favorability with Republicans, and he has a favorability of 58% with independents, and his net favorability is +17. It is not entirely surprising that Rubio already has net negative favorability overall (-6), and his fav-unfav with independents is 29-50. Once the general election begins, that could change, but it isn’t a promising beginning for the politician who predicted the “single greatest pushback in American history.”

As I said before, I think Rubio did everyone in Florida a service by making Crist reveal how exceptionally opportunistic and unscrupulous he is, but for Republicans it might be worth asking how much sense it made to challenge and ultimately run off a popular candidate in a seat that ought to have been an easy hold for the GOP. Now it is possible that the easy Republican hold could effectively become a Democratic pick-up, which would be the fourth Republican-held seat in Congress and the second in the Senate lost on account of making the stimulus a major litmus test. Given the nature of Crist’s support and the likelihood that the Democrats will still control the Senate next year, it seems more than likely that Crist would caucus with the Democrats.

It would be easy to understand why. When Lieberman left his party to run as an independent, he could still count on a number of Congressional Democrats to support him over Lamont (including Obama) in the general election, but every state or national Republican of any consequence has dropped Crist like a hot brick. The curious thing about this is that Crist and Lieberman are doing almost exactly the same thing (even though Lieberman waited until after losing the primary election), but Lieberman was much more sharply at odds with his party base over a far more significant issue than Crist was.

In the view of Lieberman fans, this is what made his self-serving move defensible, but it actually shows how much worse Lieberman’s independent candidacy was than Crist’s is today. Lieberman was profoundly at odds not only with his party, but also with most of his state on the Iraq war, and he simply refused to accept this. Had the Republicans had any self-respect and run a halfway credible candidate of their own, Lieberman’s gamble would not have worked.

National Democrats are not throwing all their weight behind Crist, and there is no steady flow of whining op-eds from every liberal pundit that Charlie Crist has been “purged” as there was among conservative writers on behalf of Lieberman four years ago. Of course, if this polling is accurate there may be no need to do this, and it could prove to be a win-win scenario for Democrats: either Crist fades, and Meek picks up most of his supporters while Crist continues to pull away enough normally Republican-leaning voters, or Meek falters and Crist wins. Most of the undecided vote is coming from moderates and liberals, which are the ideological groups Crist is easily carrying right now, and from independents and Democrats, which are groups that give Crist twelve and nine point leads over Rubio and Meek respectively. Rubio is at 34%, and he may be at or near his ceiling of support in a three-way race. How will Rubio and his fans make sense of the result if the great pushback ends up being against Rubio?

* I say unfortunately because Crist seems to have suffered no loss of public approval from his self-serving party change, and not because I have any horse in this race.