Early in February I was walking down a street in San Francisco, and I passed a T-shirt-and-tchotchke shop with a wide selection of anti-Trump-themed baseball caps in the window. Some were amusing, some were angry, but the one that caught my eye read: "America Was Never Great." And it struck me that if you paired that cap with Trump’s own, you would have a pretty good summary of how Trump supporters view American history on one hand, and how many American historians view it on the other.

Hillary Clinton tried to offer an alternative by saying variations of "America has never stopped being great" and "America is getting better every day" at her campaign events. But though she did win three million more votes, those sentiments never got much traction; I never saw them summarized on a baseball cap. What "Make America Great Again" encapsulated managed to fire up just enough people in just enough places that it won the election. And while I was as stunned as anyone on election night, as a historian I shouldn’t have been. We had no compelling counternarrative to offer in 2016 and haven’t really for some time.

It’s worth thinking about why, even as many — most? — members of my guild were keen to reject Trump’s view of history, we were uneasy embracing Clinton’s frankly patriotic version. In the face of the most fundamentally anti-American presidential campaign perhaps ever — Earl Browder got less help from Moscow when he ran for president than Donald Trump apparently did — waving the flag for many of us felt uncomfortable, or certainly unfamiliar. The best we could do was to challenge the Trumpistas to be specific: When, exactly, was American great? We would show them otherwise.

The tale of how historians got here is familiar. In the mid-20th century, the experience of the Great Depression, the Second World War, and the Cold War shaped a generation of American historians collectively known as the "consensus school." They cast American history as a Whiggish triumph of common sense over extremism, of pragmatism over ideology. In books like Henry Steele Commager’s The American Mind (1950) or Louis Hartz’s The Liberal Tradition in America (1955), the American past looked almost as quiescent as the America of their day.

There was never as much consensus within the consensus school as the next generation of historians insisted there had been, but that was part of the Oedipal point. Historians who came of age during the civil-rights struggle, who grew up with the terror of nuclear war, and who marched against the American debacle in Southeast Asia rebelled, both against American society as they found it and against their teachers. ...