An interesting essay from Politico's Roger Simon that's getting some traction on Twitter:
[T]he Iowa caucuses do not pick winners as much as they eliminate losers. And the Iowa caucuses Tuesday are likely to eliminate from serious contention the only two men who might have blocked Romney’s path to victory: Newt Gingrich and Rick Perry.
With those two out of the way, Romney faces Ron Paul, who could come in first, second or third here on Tuesday or Rick Santorum, who could do the same.
But neither of those men has a credible route to the nomination no matter how well they do in Iowa.