Manchester, N.H.

There is something exhilarating about attending a Bernie Sanders campaign event for the first time, even for an incorrigible conservative like me. The crowd is larger, louder and weirder than the typical primary election gathering. There are sweatshirt-wearing college students, cantankerous geriatrics, bedraggled parents of toddlers, hipsters with multiple facial piercings and purple-haired 20-somethings of indeterminate gender. When I arrived at the Bernie rally in Milford, N.H., an all-female rock band...