U.S. President Donald Trump continued his assault on the global economic order this week, announcing steep tariffs on a range of countries.

The issuance of letters on Truth Social, the social media company he owns, alerting countries to new tariffs on their exports to the U.S. is a break with diplomacy as commonly recognized in both form and substance.

Despite his continuing disregard for those norms and practices, there remains a desire among other nations to work with Trump to strike deals, preserve relationships and maintain order. That may be the triumph of hope over experience, but abandoning that outlook would be the most devastating blow of the Trump presidency. The world cannot submit to his capriciousness and narcissism.