We're down to five plausible nominees and four candidates whose presence in the race lacks a purpose. Rudy Giuliani remains No. 1, in part because he's the only candidate of the top three who seems to have struck a good balance between strategy and personality.

These rankings are ordered by likelihood of winning the Republican primary and are based on a number of factors, including organization, money, buzz and polling. Click here for Democratic rankings.

RUDY GIULIANI -- He's had a great two weeks: acting like a president in London; aggressively challenging MoveOn and therefore burnishing his anti-liberal, tough-guy image; and going before the critical (and critical) National Rifle Association. And his opponents aren't lifting a finger. It's remarkable how easily they're letting Giuliani define the contours of the Republican race. BTW: Will any major Christian conservative leader endorse Giuliani before the primaries begin? If none do, what does that say about the state of the movement?

FRED THOMPSON -- Thompson has lost the elite primary, but he's OK with grassroots Republicans so far. Which one is the trailing indicator? Can anyone tighten him up on the stump? His gaffes come one after the other, he often contradicts himself from one thought to the next, and the national press coverage has been savage. The Florida trip was a disaster; there's no sugarcoating it. An electorate begging for authencity isn't going to buy the notion that he didn't know much about the Terri Schiavo situation. And the Everglades oil drilling comment was just bizarre.

Continue reading our White House '08 race rankings.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.