Adam Nagourney asked an interesting question in yesterday's New York Times.

"What if Iowa settles nothing for Democrats?"

As of now, the question has no answer. It is a device for Nagourney to make the following, worthwhile observation:

What if at the end of Thursday, the three leading Democrats -- former Senator John Edwards and Senators Hillary Rodham Clinton and Barack Obama -- are separated by a percentage point or two, leaving no one with the clear right of delivering a victory speech (or the burden of conceding)? A number of polls going into the final days have suggested that after all of this, the Democratic caucus on Thursday night could end up more or less a tie.

In truth, amid all the endless permutations of outcomes that are being discussed -- can Mrs. Clinton, the putative front-runner, survive a third-place finish, or Mr. Edwards a second-place one? -- aides are beginning to grapple with the frustrating possibility that all the time, money and political skill invested here might prove to be for naught when it comes to identifying the candidate to beat in the primaries and winnowing the top tier.

This is a great point. For months, I have asserted that an Iowa victory is a necessary condition for Obama to be nominated, but a sufficient condition for Clinton. I always assumed - unthinkingly, in retrospect - that somebody would win Iowa. But Nagourney articulates a question that a lot of us have probably been wondering: what happens if nobody really wins? How will the remainder of the race be influenced?

This question is actually all about momentum, a subject I have recently covered in depth (See Part 1 and Part 2 of "A Primer on Momentum"). I'd like to draw upon those considerations to make a few comments on Nagourney's interesting article.

First, the prospect of Iowa not influencing the race should always have been considered possible, if not likely. As I noted in Part 2, Iowa generally has not been influential in either party's nomination battle. Occasionally, it has affected New Hampshire - as it clearly did in 2004 - but this is a relatively rare phenomenon in the modern era.

Second, we must emphasize the media's role in determining who "wins" Iowa, or any other state. Nagourney punts on this subject later on when he argues that Bill Clinton, "proclaimed himself the winner after coming in second in New Hampshire." Well - sure Clinton proclaimed himself the winner. But the only way that proclamation stuck was that the media agreed with it - which goes to show that, in situations like this, the perception of the media is as good as reality. Iowa will be a push if and only if the media interprets it as such.

This is why I took Nagourney's article to be especially valuable. He raises some good points, for sure. But it is also important that he raises them. Nagourney is one of the nation's top political journalists. If he is anticipating that Iowa might be a push - that is a sign that he, and the rest of his fellow journalists, could ultimately interpret it as such. This is why I would disagree with Tom's comment yesterday that, "the idea of a "push" is antithetical to how the media operates." If Nagourney is willing to consider the idea - the press might eventually embrace it.

Third, the fact that we cannot answer Nagourney's question is indicative of a point I made in Part 1: we simply do not know that much about how momentum works. Our dataset is just too limited to infer what an Iowa push will mean this year.

Nevertheless, we can make use of our knowledge about momentum to frame the question a little more precisely than Nagourney does. We know that the effect of momentum begins with the individual voter. We also know that the next contest - and thus the one to be affected by Iowa directly - is New Hampshire. Finally, we know that the 800-pound gorilla in the room is Hillary Clinton. Ultimately, what will be of decisive importance is how voters view her. So, our precise question is: how will an Iowa push affect New Hampshire voters' views of Hillary Clinton's candidacy?

You can make a convincing case that an Iowa push hurts Clinton via several of the five types of individual-based momentum discussed in Part 1; but, you can make a similarly convincing case the other way. That's exactly the point. We do not know enough about momentum to draw a firm conclusion. Nor, for that matter, do we know enough about what New Hampshire voters are thinking at this moment. While reams of polling data have poured forth from the Granite State - most of it probes the basic horse race questions that interest the media. Hardly any of it touches upon voter psychology - and so hardly any of it helps us gauge how New Hampshire voters will react to a Hawkeye push.

At the least, though, we know what to watch for. We should watch for how the media interprets the Iowa results. If the media calls it a push, it's a push. If it doesn't, it isn't a push. Our personal interpretations will not matter - the collective interpretation of journalists and pundits will. We should also watch for any trends that appear in the New Hampshire polls. We should have time for a round or two of post-Iowa New Hampshire polls. They will be our first and best clues on how New Hampshire has reacted to the results of the caucus.