Of all the rhetorical battles Donald Trump is engaged in at the moment, the one with central bankers may be the dumbest. They, after all, got the U.S. president elected.

Trump fans may love his verbal assaults against women, civil rights leaders, Chinese officials and offending CEOs. But his broadsides against the Federal Reserve ignore the central role that quantitative easing in Frankfurt, London, Tokyo and Washington played in delivering him into the White House. QE is arguably exacerbating the conditions fueling populist backlashes around the globe.

Consider the original monetary sinner, the Bank of Japan. Granted, as I recently wrote, Japan is that rare developed nation that's so far avoided a Brexit moment. Hyper-polite Japanese tend to favor harmony over political rancor. The nation's relative egalitarianism also acts as a social-backlash cushion. But even here, polls suggest tensions rising as Prime Minister Shinzo Abe's pledges to restore healthy growth for four years now prove hollow.