That's a screenshot from Sen. Jim DeMint's Senate Conservatives Fund PAC, and it's an odd strategy indeed.
Let's game this out:
Rubio is currently the comfortable frontrunner for the GOP nomination. If he defeats Crist, he's money for the Senate. Democratic nominee Kendrick Meeks won't present much of a challenge.
But here's the deal -- Crist is still a fairly popular governor. If he jumps to the Democratic Party, that gives Rubio a free shot in the primary, but he's going to win that anyway. But rather than have an easy romp in the general, he'd have to face Crist. And the general election isn't a closed Republican election dominated by conservative activists. Independents and moderates like Crist, and Democrats will fall in line.
But by all means, DeMint should continue taunting Crist. As I've said, there are only two people who can win this seat -- Crist and Rubio, and Crist won't win it as a Republican. Given the choice of the two, our choice shouldn't be hard.
Update: Jeb Bush is piling on Crist:
The former governor of Florida does some helpful tackling for Marco Rubio, spending several minutes with a Newsmax interviewer to make the point that Crist’s support of the 2009 economic stimulus can never be forgiven. It emphasizes how much Rubio’s “insurgent” campaign is one of various Republican Party interests against Crist’s machine. And it’s interesting that Bush singles out “giv[ing] the president a huge victory” as a reason Crist should have opposed the stimulus package.
Giving the president a huge victory is unforgivable, even if it helps save jobs in Florida. That, in a nutshell, is the modern Republican Party in action.