But if Trump’s goal is to turn voters against Cruz, there’s no evidence it’s working. It’s just not clear that this is an issue voters are particularly interested in litigating, though, unlike with the birther movement that centered around Obama during the 2008 election — and there’s just too much goodwill for Cruz here in Iowa. The same genre of attack that destroyed the likes of Jeb Bush seemingly can’t be applied to Cruz, whose supporters are much more committed and less tenuous than Bush’s.

“[Trump] goes after everybody, even poor people who have handicap issues,” said Mary Lawson, 59, before Cruz’s appearance in Sioux Center. “He says some awful things. I don’t want that as our president, can you imagine?”

“Ultimately any time [Trump] attacks anybody it’s because something good is happening with them and that’s why he does it,” said Jim Bolkema, 61, after the same event. “So the moment somebody starts emerging, that’s when he goes on those kind of attacks. I’d say if [Cruz] is getting those kind of attacks from Donald Trump, he should be happy, because that means he’s scared of him.”

“I would care if I thought it was legitimate,” said Vickie Froehlich, 61, who drove from Minnesota to see Cruz in Pocahontas, Iowa, on Thursday. “But I don’t. And I admire Mr. Cruz, who has said he is not attacking people.”