President Trump unveiled his new “liberation day” tariffs on Wednesday, and they are another large step toward a new old era of trade protectionism. Assuming the policy sticks—and we hope it doesn’t—the effort amounts to an attempt to remake the U.S. economy and the world trading system. All details aren’t clear as we write this, but Mr. Trump’s tariffs look “reciprocal” in name only. First he’s hitting every nation in the world with a 10% “baseline” tariff to sell in the U.S. market. For those he calls “bad actors,” he’s adding up the country’s tariff rate on U.S. goods, plus...