“Bernie! Bernie!” the crowd chanted in Council Bluffs, Iowa on the campaign trail last week. But Bernie Sanders demurred. “It ain’t Bernie, it’s you. It’s not me, it is us.” The crowd responded with a new chant: “Not me, us! Not me, us!”

A similar exchange took place at each of the two campaign kick-off rallies the previous weekend, first in Brooklyn and then in Chicago. In Iowa, Bernie gave a rationale for his response. “The truth is that the powers that be,” he said, “they are so powerful, they have so much money, that no one person, not the best president in the world, can take them on alone. The only way we transform America is when millions of people together stand up and fight back.”

No viable presidential campaign has ever been so encouraging of agitation from below.