The exit polls in Michigan and Mississippi asked voters who they’d pick in a two-way race between Trump and Cruz, also giving them the option to say they’d sit out the race. Among Rubio voters, on average between the two states, about 75 percent said they’d still vote in a Trump-Cruz race, and of those, 80 percent would prefer Cruz to Trump. Kasich voters were somewhat more equivocal; 55 percent said they’d still vote, and of those, two-thirds would go to Cruz over Trump. Although this is the first time the exit polls have asked about one-on-one matchups, the results are consistent with national polls showing Trump losing ground as the field winnows, as well as exit polls in previous states showing Trump being unpopular with Republicans who aren’t already supporting him.
What would the rest of the map (and more importantly, the delegate tally) look like in a potential two-way race between Trump and Cruz? I’m not ready to predict that. Beyond Florida and Ohio, which vote on Tuesday, there isn’t much polling in the other states. Nor has the Republican race been all that predictable along demographic lines, with Trump having performed well in states as diverse as Massachusetts, Alabama and Hawaii.
What I will do, however, is “retrodict” how the race might have gone had it been a two-man contest between Cruz and Trump all along. Could Cruz have beaten Trump in South Carolina, for instance? To do this, I’ll redistribute support from Rubio, Kasich and other candidates1 to Cruz and Trump based on the exit poll answers I described above. To repeat, these assume that most of their support would have gone to Cruz but not all of it, and also that a fair number of voters (especially Kasich voters) would sit out the race without their candidate on the ballot.