Turkey was convulsed by an attempted coup last week. Nominally democratic but in practice increasingly authoritarian, the government of President Recep Tayyip Erdogan has initiated a broad crackdown that goes well beyond the military. He has the makings of becoming another Vladimir Putin—except supposedly on America's side, but even that is up for debate.

Turkey's dubious evolution should remind Americans how hard it is for U.S. officials to play social engineers to the world. Instead of constantly meddling in hopes of "fixing" other nations, Washington should step back when its interests are not vitally affected, which is most of the time. The physicians' injunction, "First do no harm," would be a good principle for American foreign policy.

Ankara joined NATO during the Cold War. The U.S. was not much concerned about whether Turkey was a democracy. Washington wanted to secure the Balkans and project U.S. power into the Middle East. Containment of the Evil Empire was the principal objective.