Let me play off of Jay's post to second the notion that the growing conventional wisdom that Hillary is unstoppable is at best massively premature and at worst flat wrong. In fact, it's altogether possible we may look back at this past week, with Hillary basking in the media's rave reviews of her Sunday talk show PR extravaganza and the congealing CW anointing her the Democratic nominee, and see it as the high point of her candidacy.

Again, to Jay's point, the polls right now dictate the chatter, but they hardly give any indication about where we're headed. Let's take a quick look back at the trajectory of the '04 race in Iowa. In late October 2003 - still another four weeks from where we are in this year's race - Howard Dean and Dick Gephardt were running neck and neck, with John Kerry a distant third and John Edwards a very distant fourth. The race remained frozen in that position through the beginning of January as shown by an Iowa Poll taken just two weeks before the caucuses. Another Iowa poll taken just days before the vote picks up on the significant movement occurring as people focused on the race. And we all know how the final results looked:

The entire field was turned upside down in the final two weeks, with Kerry and Edwards picking up 20 and 24 percentage points,respectively, and Dean and Gephardt losing 11 and 14 points, respectively.

We also know how what happened in Iowa affected the result in New Hampshire. If you look back at ARG's polling right before and after the caucuses, you see that Kerry got a 17-point bounce out of Iowa, Edwards picked up 7 points, Dean dropped 3 points and Clark dropped nine - which is right about where they all finished just a day later:

So it's nuts to sit here in September and say Hillary can't be stopped. We don't know whether she can be stopped, and we won't know whether she can be stopped until we get within a couple weeks of the caucuses and watch as voters start getting serious about making their choice.

Earlier this week I spoke with a consultant from the Obama campaign (who asked to remain anonymous) who described it this way: "It's like going to the store to buy a candy bar. You may intend to buy a Snickers, and you may have seen a thousand Snickers ads, but when you get to the counter and see all of the different choices sitting there, you may decide you want something else."

That's particularly true in Iowa, where the caucuses are a fluid process that is far different from individuals casting a vote behind a pulled curtain.

Now consider how all of this could work against Hillary. She has massive leads in the national polls and in New Hampshire and Florida. But the one place where she's in a real dog fight is Iowa. A win there would probably clinch the nomination. But if she enters as the national front runner and the prohibitive favorite and suffers an upset in Iowa - especially a bad one - it could cause her entire campaign to unravel. Especially if, as it looks now, the caucuses are held in very close proximity to the New Hampshire primary and she has no time to stanch the bleeding. So for all the talk of other candidates seeing Iowa as a "must win," it may turn out that Hillary needs a win there most of all.