John McCormack does the math over at the Campaign Standard:

McCain's greatest advantage lies in the states that award all of their delegates - 373 in all - to the winner of the statewide popular vote: Arizona (53), Connecticut (30), Delaware (18), Missouri (58), Montana (25), New Jersey (52), New York (101), and Utah (36).

Polls have shown McCain leading in all of these states, except Utah where Romney is up big, Delaware where Giuliani was ahead, and Montana where caucusgoers haven't been polled. If the polls are right, and assuming McCain and Romney split the remaining delegates, McCain would be leading by at least 300 delegates after February 5. And a close look at the rest of the Super Tuesday states makes that a generous assumption in Romney's favor.

Go read the whole thing, he breaks it down even further. Unless something significant happens tonight, Romney isn't going to turn this thing around. And the McCain campaign is acutely aware of how little distance their is between them and the finish line. As Jonathan Martin reports:

NBC invited John McCain and Mitt Romney onto “Meet the Press” Sunday for a final debate before Super Tuesday. Romney, now the underdog and eager for opportunities to take on the frontrunner, immediately accepted. McCain, who appeared on the show last week and is looking to protect a lead, declined.

Sometimes playing not to lose is the prudent course of action.