In presidential politics, political mavens like to talk about “tickets out of Iowa,” as in: “Do you think there are two or three tickets out of Iowa?” What that means is, how many candidates can remain viable after Iowa?

In this race, Mitt Romney probably ensured himself one of those if he can remain where he is in the polls ( in second, relatively close to Rep. Michele Bachmann (R-Minn.). He’s not playing hard, he’s holding a respectable chunk of the electorate and he is putting his chips on a win in New Hampshire (which, if he doesn’t win, is a big problem.)

So who else could come out unscathed? Bachmann is now the front-runner in Iowa and, as in inevitable with a surging candidate, has raised expectations. She wins and she arguably becomes Romney’s main competition. She comes in second or third and the headlines will be “Bachmann disappoints” or “Did she peak too soon?”

The real wild card in this is Texas Gov. Rick Perry. Some insiders think he’ll jump into Iowa to do “unexpectedly well for a newcomer to the race,” as his campaign would characterize any decent showing. Others think he won’t bother and will save his money for the caucuses, hoping Iowans won’t feel snubbed that he delayed his entry in the race just long enough to escape Ames. And then what? If he beats Bachhmann in what will be characterized as a big upset, he’ll be in fine shape. But if he loses to Bachmann, or worse, divides the vote so that Romney wins Iowa, he may be done. (The rest of the field could be, too, if Romney wins a socially conservative state where he’s not supposed to do all that well.)

So there is an argument that there are only two tickets out of Iowa: Romney and either Bachmann or Perry. Could Perry skip Iowa altogether to play it safe? I suppose, but that would contradict his message that he’s the conservative unifier who can bring all strands of the party together.

And those who come in fourth or worse? Chances are, their luster fades, the money dries up and the media ignore them.

You can understand, then, why Perry is pondering the timing of his entry into Iowa. It might be the most important decision of any candidate before the real votes are cast next January.