Whether the subject is North Korea, Iran, the North American Free Trade Agreement or tariffs, the razzle-dazzle diplomacy of feints, tweets and rants is likely to continue. And while Mr. Trump is not wrong to experiment with unconventional diplomatic strategies, he—and we—may find that this approach carries some unexpected risks.

The president’s chaotic negotiating style seeks to pressure opponents to settle by creating uncertainty while concealing his own intentions. This aligns with his political style, which aims to keep the public enthralled through drama and suspense. He also believes in flooding the zone. While other presidents might avoid simultaneous fights with Europe over the Paris climate accord, steel and auto tariffs, and Iran policy, Mr. Trump believes that the more issues are in play, the better chance he has of making good deals.

Perhaps. But the steady increase in U.S.-generated tensions and uncertainties over trade and security could also produce bad or even catastrophic outcomes as they interact with the economic and political risks that have been steadily accumulating across the globe.