I entered Martin Gurri’s world on August 1, 2015. Though I hadn’t read The Revolt of the Public, at the time a little-known book by the former CIA analyst of open news sources, I hit a disorienting moment of a type he’d described in his opening chapter. There are times, he wrote, “when tomorrow no longer resembles yesterday… the compass cracks, by which we navigate existence. We are lost at sea.”

Gurri’s book is about how popular uprisings are triggered by collapses of faith in traditional hierarchies of power. I felt such a collapse that day in Waterloo, Iowa, covering the Republican presidential primary. The first debate was five days away and the man expected to occupy center stage, Donald Trump, held a seemingly inexplicable six-point lead.

Two weeks before, on July 18th, Trump lashed out against former Republican nominee John McCain. Even McCain’s critics considered his physical and mental scars from years as a Vietnam war prisoner to be unassailable proofs of his patriotic gravita…