Continuing his excellent series, the Washington Post's Chris Cillizza makes the case for Charlie Crist. Key passage:

Conventional wisdom heading into this fall's presidential election is that Florida is McCain's to lose -- especially given the lingering tensions between supporters of Barack Obama and backers of Hillary Rodham Clinton. Clinton remains extremely popular in Florida -- particularly among the state's influential Jewish and Hispanic voters -- and polling has long suggested she would have been a more formidable foe against McCain than Obama.

But, two recent developments suggest that Florida may not be the cakewalk for McCain that many observers believe.

The first is the report that seven (seven!) times more Democrats have registered to vote than Republicans since the first of the year in Florida. Democratic registration increased by more than 100,000 in that time while Republican registration grew by less than 17,000.

The second is Obama's decision to advertise aggressively in the state. His latest ad, which hit Sunshine State airwaves yesterday, touts his bipartisan work with Sen. Dick Lugar (R-Ind.) to secure loose nuclear materials.

Obama's willingness to spend money and campaign extensively in Florida coupled with Democratic registration gains there suggest that the race could be far more competitive than currently assumed.

Regardless of whether you believe Florida is a genuine toss-up or a leaning Republican state, adding Crist to the ticket helps.