Perry and Christie: The candidates whom Trump has hurt the most

These voters came to Mr. Trump from all of the other candidates, but a disproportionate share of voters for Mr. Perry and Chris Christie abandoned them for Mr. Trump. Mr. Perry lost more than 60 percent of his May support to Mr. Trump, perhaps a harbinger of things to come.

Mr. Christie lost 57 percent. In contrast, Jeb Bush lost only 14 percent of his early support to Mr. Trump, the least of any candidate. (Granted, Mr. Christie and Mr. Perry did not start with large numbers of voters in this survey, so any defections made a bigger dent in their shares.)

The survey also asked people to choose a runner-up for their vote in the primary. Among those whose first choice was Mr. Trump, some said they would return to the candidate they sided with in May. Nearly 60 percent of the Ted Cruz supporters from May who switched to Mr. Trump said they would return to Mr. Cruz if their first choice were eliminated. Mr. Christie and Mr. Bush would get about a third of their straying voters back, while Mike Huckabee and Mr. Perry would see less than a fifth come home.