Some new numbers:

The American Research Group released their latest statewide survey this afternoon. The poll sampled 600 likely primary voters from September 1-4, with a MoE of +/- 4%. Gov. Romney continues to lead with 39%, which is an increase of 15 points from 24% in May. May Sept. May/Sept. Change Gov. Romney 24% 39% +15 Giuliani 19% 13% -6 Thompson 8% 12% +4 McCain 22% 9% -13 Other 12% 14% +2 Undecided 15% 13% -2

In second place, this is the state of McCain’s last best chance, according to Mark Hemingway . He writes:

even though Romney seems to lag at third in national polls behind Giuliani and Thompson, he’s running ahead of everybody in Iowa and New Hampshire. If Romney wins in Iowa and then Michigan before heading into New Hampshire, his momentum could be unstoppable. But McCain needs to win Michigan just to be taken seriously — unlike Romney who might have real momentum. In the end, McCain stopping — or at the very least cutting significantly into — Romney in Michigan may ultimately not benefit McCain, but one of the other front-runners looking for someone to put a halt to Romney’s early primary state momentum.
As of right now, McCain has everything to lose if he doesn’t win Michigan, while Romney has everything to gain by a victory. And what makes all of this truly interesting is that McCain and Romney’s respective campaign people in Michigan are engaged in all-out blood sport against each other.