Des Moines Register Poll

The Des Moines Register Poll came out Saturday night and it shows Mitt Romney as the nominal leader at 24%. Ron Paul is second in the poll at 22% but the more recent two nights of polling (the poll was conducted over four nights) shows Rick Santorum still surging garnering 21% and Paul fading a bit.

So what are we to make of all this?

First, as Nate Silver points out, even with the best polls, there are a variety of reasons to be cautious in treating a polling result as a prediction. The most important reason in this case is that the poll was taken over four days with the most recent interviews conducted a full four days before the caucus. This is a particularly volatile electorate as 41% of caucus-goers said they could still change their minds.

But there are some things we can probably draw from this poll:

1) Romney's ceiling: Romney attracted 24% in the poll on the first two nights ... and on the second two nights. We can expect everyone's numbers to go up just a little bit as the undecideds find a home but it is clear that Romney is not going to go significantly higher. A really good guess for Romney's topline on Tuesday night is 28 - 30. I'd guess 28.

2) Paul's ceiling: This poll is particularly good for a lot of reasons. One of them is that it includes cell-phone only voters. Paul did a bit worse in the second two nights of polling as his crazy newsletters got more coverage and as Santorum's surge got more coverage. Paul is not likely to go away as his supporters are somewhat unique but he probably won't move much higher either. Moving lower is possible. A really good guess for Paul is probably right around what he got in the poll here ... 20 - 24 is my guess. UPDATE - Paul actually did a lot worse the second two nights. I'd revise my estimate for him down to 17 - 21. The attacks on him are taking a bigger toll that I had thought.

3) Santorum's surge: Santorum is the only one with real upside. He got just 15% in the four-night sample but did A LOT better on the last two nights. I have a good theory on what is happening. Conservatives who don't like Romney had gone from Bachmann to Perry to Cain to Gingrich and a few went to Paul when he surged. Now they are moving to Santorum. Bachmann, Gingrich, and Perry are not doing very well in this poll but there is still a combined 30% slice of likely caucus-goers supporting these three also-rans. The shift of some of their supporters moving to Santorum is what has fueled his surge in recent days. As more of those 30% see that Santorum is the conservative with the best shot (the Des Moines Register poll will get lots of coverage, especially in Iowa), I think some of those supporting these voters will move to Santorum. Will it be enough for Santorum to catch Romney? I doubt it ... but it is possible.

4) Partly for the reasons in #3, Gingrich, Perry, and Bachmann are done. Gingrich is the most likely to keep going as polls in South Carolina still show him in the lead. That will change quickly with a 4th or 5th place finish in Iowa though. Perry could keep going as he has money. It is hard to see what his path to the nomination would be but remember, logical reasoning is not his strong suit. Bachmann will likely pack it in.

5) Huntsman is still running for President. Seriously.