WASHINGTON — President Trump has gone overseas to embark on some of the most consequential diplomatic negotiations of his tenure, threatening an all-out trade war with allies and seizing a chance to make peace with a nuclear-armed menace.

But back home, he left behind a West Wing where burned-out aides are eyeing the exits, as the mood in the White House is one of numbness and resignation that the president is growing only more emboldened to act on instinct alone.