Kelly Ferro is a busy mom on her way to the post office:leather mini-backpack, brunet topknot, turquoise pedicure with a matching ombrémanicure. A hairdresser from Kenosha, Wis., Ferro didn’t vote in 2016 but hassince become a strong supporter of Donald Trump. “Why does the news hate thePresident so much?” she says. “I went down the rabbit hole. I started doing alot of research.”

When I ask what she means by research, something shifts. Hervoice has the same honey to...