College kids and aging Woodstock hipsters are massing. The media are chattering. Excitement is (sort of) building. Welcome to the boomlet for Bernie Sanders, in which Democrats frustrated with the coronation of Hillary Clinton try to conjure a repeat of the Barack Obama campaign magic of 2008. Could a 73-year-old self-avowed socialist from Vermont really win the Democratic presidential nomination?

The short answer is no, but then we live in curious political times. That America’s most left-wing Senator is rising in the polls...