It's not hard to figure out that a governor who is running for the same Senate seat that he must now fill by appointment can't choose himself -- nor someone who has ambitions beyond the end of Martinez's term. Crist has to appoint a pro-Charlie Crist "caretaker" of a senator.
But a year and a half in the U.S. Senate can do funny things to the mind. Having worked there years ago, I can attest that life is pretty good for senators. Should Crist encounter some major drop in popularity, might his caretaker change his or her mind about stepping aside?
More likely is that the powers behind Martinez urged him to put Crist in a box by forcing him to do something he usually doesn't enjoy: making a tough decision quickly. Recall that Martinez was born in Cuba, and he has strong ties to Florida's old-guard Cuban-American power structure -- a network that is no fan of Crist and a major sponsor of Rubio.
Based on what we've seen in elections across the nation following the November 2008 election, voter turnout has dropped off. Plus, the GOP appears to be moving back to being an activist right-wing party. If Florida's senatorial primary brings a low turnout of mostly hardcore conservative voters, and if Rubio's campaign can put together a credible fundraising effort -- likely to come from Washington, D.C., and other major centers of well-organized conservative fundraising -- then the Miami former House speaker could turn this contest into a horserace.
In a sense, this is all unfortunate for Republicans. Crist, after all, is far more likely than Rubio to win over independent voters -- Florida's key swing demographic -- in the general election. But conservatives are now energized over "Obama Healthcare." Too, they sense their new role as antagonists to what they see as the most liberal president and Congress in their lifetimes. Charlie Crist's quest for the Senate might be the ultimate test case of the direction Republicans want to go as they prepare for 2012.