Trump's ambassador broke every rule of diplomacy in Warsaw

On May 29, the lower house of Poland’s parliament voted 428-3 to honor the 250th anniversary of American independence. Nobody voted against. Watching from the gallery was Tom Rose, the U.S. ambassador who had spent the previous four months in an open, personal feud with the marshal who announced the result.

Rules of professional diplomacy say that a combination is impossible. An envoy who attacks the speaker of a host parliament in public is understood to have forfeited the relationship. Rose attacked him twice, in writing, by name, and the relationship did not move an inch.