For most of the last 18 months, Donald Trump has been portrayed as a clown, a showman, an opportunist, a faux conservative, a political naïf, and an egomaniac bent on nothing but power and glory—but rarely as a man with an intelligible ideology. Yet if Trump’s ideas can’t quite be said to cohere into a unified worldview, and if his legion flip-flops deny him any claim to philosophical consistency, many of his signature promises and policies do add up to a set of ideas—populist, nationalist, authoritarian—with deep roots in American history. After a year and a half of dwelling on Trump the personality, it may be time to turn our attention to Trumpism.

To the extent that analysts have discerned any new philosophy behind Trump’s rise, they have focused on the vicious, bigoted internet stylings of the so-called alt-right. But the unabashed white nationalism, anti-Semitism and misogyny of that hitherto underground movement constitute only one strain of Trumpism. The larger ideology that the president-elect represents is a post-Iraq War, post-crash, post-Barack Obama update of what used to be called paleoconservatism: On race and immigration, where the alt-right affinities are most pronounced, its populist ideas are carrying an already right-wing party even further right. On a few economic issues, such as infrastructure and entitlement spending, they could direct the party toward the political center. On trade and foreign policy, they threaten to demolish the internationalism that has governed the GOP since Dwight Eisenhower’s presidency. In each of these ways, Trumpism represents a significant break with the conservatism that has dominated the Republican Party for decades. 

Where did these currents come from? Today’s populist right has its clearest origins in an early 20th-century backlash against a society that was becoming centralized, urban, cosmopolitan and interconnected with the world at large—tendencies that are still upsetting white rural America today. Just as Trump was boosted over the wall of 270 electoral votes by white Midwesterners, some of whom had previously voted Democratic, so it was formerly progressive elements from the country’s midsection that fueled the rise of a right-wing populism after World War I. That movement was never strong enough to win the White House, and it was largely discredited and marginalized by World War II. But in today’s post-Great Recession globalized world many of its ideas are suddenly reemerging with a vengeance. And now, for the first time in history we have a president, commanding all the powers of the Executive Branch, who espouses its ideas. That could mean a rollback of the core tenets of post-New Deal, post-World War II America, including the commitment to civil rights, civil liberties, and pluralism at home and to liberal internationalism abroad.

The conservative populism from which Trumpism derives began as a mutation of the progressivism of the early 20th century. Progressivism is the name we give to the bipartisan reform movement in the century’s first decades that called for an activist president and a strong federal government to address urgent new social and economic problems brought on by the industrial revolution. Led first by Republican Theodore Roosevelt and then by Democrat Woodrow Wilson, progressivism sought to tame corporate power, protect workers, assimilate immigrants, provide new social services, expand democracy and, on the global stage, bring order to a fractious world. Both the idea of a strong federal government and the specific goals that progressives cherished would also undergird Franklin Roosevelt’s New Deal and, in time, postwar liberalism more generally. 

But as the nation journeyed from progressivism to New Deal liberalism, not everyone came along for the ride. After World War I, many Midwestern and western progressives of a populist bent swung hard to the right, retaining in some cases their economic egalitarianism but also taking up reactionary stands on cultural and foreign-policy issues. “Somewhere along the way,” as Richard Hofstadter wrote in his classic work The Age of Reform, “a large part of the Progressive-Populist tradition has turned sour, become illiberal and ill-tempered.” ...