He’s at 42 percent, with DeSantis at 19 percent and Scott at 9. Both DeSantis and Scott have big chunks of the electorate saying they are their second choice or that they are actively considering them. Both also have high favorable ratings comparable to Trump’s. It’s a major advantage for Trump that two-thirds of his vote is locked in, but about a third is persuadable.

[First off, we’re still dealing in the category error of summer polling for a winter contest. Second, and more importantly, Iowa uses a caucus, not a primary. The campaign that organizes in Iowa is the one that usually wins, and DeSantis is organizing massively there and in other early states in the cycle. Polls matter less in caucus states for that reason. — Ed]