In the aftermath of the 2012 election, when just about everyone assumed Mitt Romney lost because he didn’t win enough Hispanic votes, the election analyst Sean Trende produced a dissenting take. A close look at the results across the Midwest and Appalachia revealed a large population of what Trende called “missing white voters” — a mostly working-class constituency that simply declined to turn out in the Romney-Obama contest, and that a future (and more populist) Republican might win.

Trende was misunderstood by certain critics as making a normative argument that the G.O.P. should double down on being a white party. In reality, he suggested that a Republican Party with a more populist economic message might win the missing whites and more minority votes as well.

But an explicit “double down on white voters” argument has circulated for years on the margins of conservatism, and it had obvious influence over Donald Trump’s campaign strategy in 2016. His mix of economic populism and deliberate racial polarization was supposed to be demographically foredoomed — but instead it won him precisely those regions Trende’s analysis had highlighted, and the presidency as well.

For a sense of why this happened, in defiance of so much prognostication, look at the new Pew analysis of the 2016 election, which relies on voter files to create a more accurate assessment of who actually voted. Compared to exit polls, a couple of things stand out: First, Pew has whites at 74 percent of all voters (CNN’s exit poll had them at 71 percent), and second, it has whites without a college degree, Trump’s key constituency, at 44 percent of all voters (compared to just 34 percent for CNN).