At noon ET on Monday, the US presidency changed hands, and one of the largest governments in the world rearranged itself in service to the petulance and vulgarity of the nation’s new president. At the Pentagon, a portrait of a general who Donald Trump had found insufficiently deferential to him in his first term was removed from a wall; photographs of the empty spot circulated on social media. Trump was set to sign a bevvy of executive orders, pledging to withdraw the US from the Paris climate agreement, to revoke policies promoting wind energy and electric cars, and to exert...