The U.S. State Department’s “One Flag Policy” mandates that only the American flag — except for specific instances, such as the POW/MIA flag — be flown at U.S. embassies around the world.

No, I haven’t suddenly embraced vexillology — the study of flags — as a hobby. But I have been struck by a newly conspicuous symbol on the right: the upside-down American flag. After former ...