I will not make any definite predictions, because I sincerely believe that Obama, Clinton, Edwards, Romney and Huckabee all could emerge victorious tonight. I do have my sense of what is more probable and what would be more surprising, so I will offer a few small guidelines of what I am expecting.
Democrats, first place: All three candidates have very plausible scenarios to win this out: Hillary Clinton will win if she turns out first time voters who are registered Democrats, Barack Obama if he turns out independents, and John Edwards if he rides the second-choice preferences ti victory. My hunch is that a Clinton victory at this point is the least probable scenario, mainly because realignment will play at her disfavor. To put it simply: Clinton has to be leading by at least a few points prior at the entrance of the caucuses to win a plurality of delegates which gives her an extra hurdle that her two rivals don’t have. That said, the benefits of a victory for Clinton would be huge, as she would then be in an ideal position to sweep the rest of the early states. A campaign that now looks so fragile could end up being much easier than predicted (just look at the trajectory of the Gore-Bradley match-up once Gore won New Hampshire).
Meanwhile, I would venture to say that an Edwards victory seems a bit more likely to me than an Obama victory because (1) I do believe independents will make up a larger proportion of voters than ever, but I doubt it will be as much as some are predicting; and (2) realignment should boost Edwards a bit more than it should boost Obama (except if the rumors of deals between Obama and Biden/Richardson are true, which we apparently won’t know for now).
If Obama wins tonight, it will be a huge story that would reverbate massively in later states and would put Clinton’s campaign in shambles. Obama will not have won the nomination yet at all, but he would have defeated the mighty Clinton machine and that will probably lead many in New Hampshire, South Carolina, and Nevada to take a whole new look at him. The Obama camp did take a risk, however, in letting expectations get slightly out of control in the past few days as one of the state chairs predicting a 200,000 people turnout and Obama repeatedly predicting victory. Compare that to the Clintonites are saying that they “already won just by being competitive” — which is obviously a ridiculous argument considering that they were slightly ahead in polls until two months ago, but it at least sets up their spin in case they lose.
Democrats, third place: I would be more surprised if John Edwards comes in third than if Obama or Clinton do. He is the least dependent on turning out new voters, and he should be boosted up to at least second place as many backers of unviable candidates are likely to line up behind him. However, if turnout really shoots up tremendously and new-comers flood the caucuses, Edwards has the most to lose and could easily fall to third place. The race to avoid third is just as predicated on turnout than the race to be first. And obviously, both Obama and Clinton would face lots of problems going forward if they come in third — especially if the other is the victor.
Republicans, first place: It will be Huckabee or Romney, of course, but I have very little to add to the fact that most polls show a tight race. A few days ago I would have said that Romney has caught up Huckabee and is likely to win, but Huckabee has proved remarkably resilient in the final days, the local media has barely covered Monday’s infamous press conference, and Huckabee will be victorious if evangelicals turn out. But remember that Romney’s campaign is much better organized and looks to be better equipped to get its supporters to caucus, whereas Huckabee has had much less time and money to get his team and lists together. Just because of the few points boost this could give Romney, I would say he is slightly more likely to win it tonight and keep his candidacy alive. (Update: MSNBC is now reporting that both the Romney and Huckabee internal polls have Huckabee narrowly ahead, so Huck’s lead appears very much real with a few more hours to go).
Republicans, lower-tier: The one prediction I will risk: Rudy Giuliani comes in behind Ron Paul, which probably puts him in sixth position. And however much the Giuliani campaign is dismissing results from IA and NH as irrelevant to their big-state strategy, they’re going to have a hard time spinning a sixth place showing. I wouldn’t be surprised at all if Ron Paul were to jump to fourth place. As to the McCain surge, I do think Thompson’s numbers are a bit understated in polls compared to McCain’s given that the former’s campaign is much better organized to make the most of Iowa.