In this morning’s Republican presidential debate on NBC, Mitt Romney came under fire from multiple corners. Jon Huntsman decried decisive rhetoric while touting his bold tax and entitlement reform ideas that were more conservative than anybody else on stage. And Texas Gov. Rick Perry made an articulate — and at times, forceful — case that he was the consistent conservative outsider in the race. Had this all happened in September, we may be looking at a race where Perry had just won Iowa and was well ahead in South Carolina, while Huntsman was nipping at Romney in New Hampshire. But this isn’t September.

Instead, over the past several months, rivals hardly laid a glove on Romney. Perry had one disastrous debate performance after another and dropped like a rock in the polls. After a succession of candidates rose and fell, eventually Rick Santorum emerged as the leading conservative alternative to Romney. And Huntsman, boring and obnoxious in debates, never took off in New Hampshire. So what we’re left with is a situation in which Romney is so far ahead in his quest for the GOP nomination, that barring a major catastrophe, he’s unlikely to lose. In football terms, he’s in the prevent defense — able to surrender lots of yardage to his opponents in the middle of the field and still win as long as he doesn’t turnover the ball.