Michigan is one of the most interesting four-way fights this month. The polls suggest a Trump win and Rubio in fourth, but little else is clear.
Trump the clear leader
Trump leads by double digits in five of six Michigan polls conducted in past week. His leads are 13 points, 15 points, 18 points, 19 points and 22 points. In one survey, by ARG, Kasich leads Trump by 2 points.
The ARG poll, in which Kasich posts 33 percent (he's at 15 percent to 23 percent in the other 5 surveys) has the smallest sample size of the six recent ones. ARG overestimated Kasich in New Hampshire, Iowa, South Carolina (by a lot) and Texas — I can't find any state where they underestimated his support or nailed it.
So the easy-double-digit Trump lead in the other five polls needs to be the starting point. This could shrink due to a late surge after Cruz's strong weekend and a steady barrage of bad news about Trump. It could shrink due to turnout effects. It could grow due to crossover voters. But this isn't like Trump's lead in Kansas polls. Those were old polls, and that was a caucus state. The only thing that could really threaten him would be massive consolidation of the anti-Trump forces. But the polls, and the delegate rules raise many roadblocks here.
Who's On Second?
While Kasich almost certainly isn't the leader in Michigan, it's not clear whether he or Cruz is in second place. In three polls they are within 2 points of one another. In two polls, Cruz is up significantly, while Kasich leads in that ARG poll. Going by their RCP averages, Cruz has a 0.2 percent lead over Kasich, well within the margin of error even for an aggregate of six polls.
Rubio is ahead of Kasich in two of six recent polls, but those are both older polls. Rubio doesn't lead Cruz in any Michigan polls, and he is in a distant fourth place in the three latest polls. How to adjudicate the fight for second? It's mostly guesswork, but I'd count on some Rubio to Cruz movement among conservative voters, pushing Cruz into second.
How consolidation behind an anti-Trump could help Trump
Rubio ranges from 9 percent to 17 percent in the six most recent polls. He's below the 15 percent threshold in all of the four most recent surveys, and his RCP average is 12.3 percent.
Trump sometimes resembles a science fiction monster that grows stronger with each bullet he takes. In Michigan, if conservatives coalesce behind Cruz, or if moderate Republicans coalesce behind Kasich — that is, if Rubio supporters move to a voter higher in the polls — that could just result in more delegates for Trump.
Michigan has a 15 percent viability threshold. That means that a candidate only wins delegates if he gets 15 percent of the vote. The state's 59 delegates are allocated proportionately among the candidates who meet that threshold.
So imagine two different possible scenarios:
Trump: 35 percent
Cruz: 25 percent
Kasich: 20 percent
Rubio: 15 percent
In that case, the 5 percent that goes to minor candidates is discarded, and the four candidates percentages are pro-rated, so to speak. The relevant ratios for delegate apportionment would be
Trump: 36.8 percent X 59 = 21 delegates
Cruz: 26.3 percent = 16 delegates
Kasich: 21.1 percent = 12 delegates
Rubio: 15.8 percent = 9 delegates
Let's say some Rubio's support flees to the stronger candidates, a bit to Kasich, and more to Cruz. You could get this result:
Trump: 35 percent
Cruz: 30 percent
Kasich: 22 percent
Rubio: 6 percent
So now, the delegates are divided only among the top three. The 13 percent among minor candidates is discarded, and so the "pro-rating" is more dramatic.
Trump: 40.2 percent = 24 delegates
Cruz: 34.5 percent = 20 delegates
Kasich: 25.2 percent = 15 delegates
In this hypothetical, Trump just got the same number of votes as before, but he got closer to 1,237 delegates because anti-Trump people coalesced behind a candidate.
But if Rubio is already below 15 percent, as the polls suggest, then consolidation behind either Kasich or Cruz would lower Trump's delegate haul. So, it's complicated.
Timothy P. Carney, The Washington Examiner's senior political columnist, can be contacted at email@example.com. His column appears Tuesday and Thursday nights on washingtonexaminer.com.