But the fact that Cornyn did take a position may have sparked even more debate about Rubio’s viability as the Republican nominee. Rubio’s lack of name recognition and untested fundraising potential means that any publicity is good publicity, said Michael Franc, Vice President for Government Relations at the Heritage Foundation.

Crist promoted a far more conservative message during his gubernatorial race than he has adhered to during his governorship, meaning that Florida voters are receptive to a more hard-line candidate, said Franc. They will be even more receptive to one in 2010.

“The kind of voters who during good economic times might have gravitated to the center or center left are going to be looking at more fundamental things” such as lower taxes and limited government, said Franc. ”They’re not going to be voting on esoteric issues like gay marriage or environmentalism.”

Senate leaders have recognized that Crist may not be a reliably conservative vote in the Senate. But Crist has sky-high approval ratings and is seen as a far safer choice in the general election than Rubio.

This leads some observers to question why Crist wouldn’t run for another term as Governor and let Rubio take a crack at the Senate seat. This point is especially poignant given Crist’s reputation as someone who is more interested in climbing the political ladder than representing the state of Florida. Crist spent one term as Attorney General before running for the governorship, where he has again spent only one term before announcing his Senate bid.

Adding Crist to the ranks of GOP moderates and defectors like Olympia Snowe and Arlen Specter may mean a diluted Republican presence in the Senate even if the party does manage to earn more seats there. And the NRSC setting a precedent of endorsing moderate candidates this early on in the election season could signal a more widespread shift to the center for the party as a whole.