We’ve been saying all along that Romney is the establishment candidate, the one with the most backing, organization, and money, which makes him by far the most likely nominee. The only actual political disagreement - as opposed to the talking point nonsense that’s drowned any real analysis - is over which opponent the extreme conservative wing will coalesce behind. It may be Bachmann or it may be Perry if he finally decides to get into the race. He keeps dipping his toe but doesn’t seem to want to get wet. Yes, Bachmann does well in Iowa, but Iowa is about as non-representative a state as can be found, which is why winners of its caucus never get farther unless they happen to be the establishment candidate who was going to take it all anyway. The poll cited by The Other Waldo Pepper is interesting evidence that she’s the likely opponent, but you can also read it as saying that Romney outpolls every one of his opponents combined, while Bachmann loses badly to the her wing combined. They all have to get behind her after their preferred candidate drops out. That’s hard to sustain and means even lower enthusiasm.
All this is based on there not being a bombshell discontinuity over the next year. Talking about it just before the default date is therefore risky. I don’t believe there will be a default - every Republican leader except Cantor has stated that it is an insane thing to let happen - but if there is no one knows where the pieces will fall after the explosion.
Other than that, the election will be Obama vs. Romney, with Obama the winner. There is simply no enthusiasm for Romney as a candidate, while Obama is raising several times as much money as him, and AFAIK, a couple of times what all the Republican candidates are raising collectively. If he were consistently behind in every poll, I might think otherwise. But he is consistently ahead in almost every poll against specific names. (Single polls mean nothing. If the universe of polls don’t say the same thing, feel free to disregard any outlier no matter how tempting it looks.)
The power of incumbancy, plus more money, plus the demographic factor that the Republicans have alienated several large groups. That’s what any Republican has to overcome. I can’t see Romney being the one to do so.