President Trump accomplished his unlikely rise to the White House powered in large part by an embrace of economic and cultural populism. Yet one year after this victory, the Republican Party still has no idea how to address or incorporate those populist elements into a coherent agenda. Nor, despite their best intentions, do Mr. Trump and his former adviser Steve Bannon.

This populism does not sit easily within the Republican Party’s business conservative wing (think Mitt Romney) or its “liberty” conservatives (think Tea Party) faction. So it’s not too surprising that virtually all of Mr. Trump’s signature populist ideas have been watered down or ignored, or are in limbo. Instead, Republicans push tax plans that overwhelmingly benefit their donor and executive class. It’s as though Jeb Bush or Ted Cruz won after all.

But they didn’t win, and they didn’t win for a reason. Republican voters want something different from anti-government or establishment Republicanism. And the voters who made Mr. Trump president, the millions of largely white men and women without college degrees who voted for Barack Obama before backing Mr. Trump, definitely do not want Romneyism with a human face.

The traditional Republican policy agenda is a political zombie, a relic that once served our nation well but is out of touch with what Americans want today. It doesn’t have to be this way. Mr. Trump and some of his supporters had good ideas for a reformed Republican Party that fuses conservative and populist elements into an alloy stronger than either on its own.