Campaign superblogger Marc Ambinder tosses out a scenario in which the GOP presidential nomination could remain up for grabs until March:

Mitt Romney wins Iowa; Mike Huckabee is second; Rudy Giuliani is third; Fred Thompson is fourth.

Giuliani wins New Hampshire, followed by Romney or Huckabee or McCain.

Romney wins Michigan; Huckabee or McCain is second.

Thompson wins South Carolina, followed by Giuliani. Romney is third....

Ambinder is following the race far more closely (and astutely) than I am, but there's simply no way that Fred Thompson finishes fourth in Iowa, and third or (very likely) worse in both New Hampshire and Michigan, and nonetheless wins South Carolina. It Just Won't Happen. The primary season is extremely dynamic, and candidates who win states (or significantly exceed expectations) get a huge boost at the expense of those who--like Ol' Fred in this scenario--look like losers. That's the whole problem with the primary calendar: Once small, unrepresentative states such as Iowa and New Hampshire create a political narrative for the race, it's very hard to break free of it. If Thompson really wants to have a shot at winning South Carolina, he's going to have to do better in the earlier states than he does in the scenario above.