Last week I pointed out three past criteria that have described the eventual nominee of either party. With the New Hampshire primary just three days away, current polls make it look like two people meet all the criteria: Bernie Sanders and Pete Buttigieg.

After the fuss over difficult tabulation in the Iowa caucus, there was some question of whether it would affect the dynamics of this year’s Democratic nomination. If not, all that fried-butter-eating, or whatever it is that candidates do, would go to waste.

Now we can see the net effect, which is to make Joe Biden’s odds substantially longer.

As I mentioned, in the past, nominees of either party have hit three targets:

• Top four in national surveys by the time of the Iowa caucus.
• Top four finishers in Iowa.
• Top two finishers in New Hampshire.

The pundit talk about Iowa being predictive leaves out the fact that when the race is close, its track record is not that great. Therefore we must count any top-four finisher as a contender.

(Note that Billionaire Mike Bloomberg is at #4 in national surveys, but he isn’t competing in Iowa or New Hampshire. If we leave him out, that puts Mayor Pete Buttigieg at #4.)

The New Hampshire primary’s not until this coming Tuesday. But at this point, the opinion polls are starting to coalesce.

CNN/UNH poll (conducted Feb. 4-7, changes since Jan. 15-23):
Sanders 28% (+3)
Buttigieg 21% (+6)
Biden 11% (-5)
Warren 9% (-3)
Gabbard 6% (+1)
Klobuchar 5% (-1)
Yang 3% (-2)
Steyer 3% (+1)

— Arjav Rawal (@ArjavRawal) February 8, 2020

If we use them to guess the top two finishers, what does it all look like in a Venn diagram?

There are two candidates in the intersection of all these sets: Senator Bernie Sanders and Mayor Pete Buttigieg. If the pattern of 2000-2016 is followed, the Democratic nominee will be one of these two.

Past processes are running more or less smoothly, in the sense that they are producing at least one viable candidate. Bloomberg might have trouble getting further traction, unless there’s some kind of deadlock where everybody turns to him. However, Warren is already available for that: preference polls indicate that she is acceptable to the highest fraction of Democratic voters.

From a pure Venn-diagrammatic point of view, the Iowa results don’t add information. But they did lead Biden and Buttigieg to switch places in the New Hampshire race. In that respect, the net effect of the Iowa caucus was to make it much harder for Joe Biden to get the nomination.

This leads to the question that’s come up in Democratic Party circles, which is whether to give such outsize influence to a state like Iowa that does not reflect the party’s diversity. It’s easy to make an argument that it would matter.

Early election results appear to give a bounce to the top 1-2 finishers, as voters in other states find out which candidates perform well in an actual election (or caucus, in Iowa’s case). If the first primary were in South Carolina and not Iowa, then presumably Joe Biden would have gotten the benefit. I would be writing about a Sanders-vs-Biden faceoff. In any event, the Iowa caucus favored the moderate liked by whites (Buttigieg) over the moderate liked by blacks (Biden) – and it’s affecting New Hampshire, a fairly predictive state.

If some other candidate eventually gets the nomination, it would identify forces not captured by the simple rule I have described. Biden had strong support in South Carolina (primary February 29), and Warren was performing in the top four in national surveys. The normal course of events at this point would be for them to decline in support. This should all become much clearer on Super Tuesday, March 3, the date of 15 more primaries nationwide.

What’s the probability of an exception to the pattern? 2000-2016 gave only 8 examples, a pretty short record. I would guess the probability of an exception (i.e. someone other than Buttigieg or Sanders) to be about 1 in 10.