It was a sendoff befitting a titan of the republic: the flag-draped coffin, the bagpipes, the angelic chorus, the stained-glass windows and gothic pillared arches encasing a sanctuary of some 3,000 notables bidding a final farewell. But the Saturday morning service for John McCain at the National Cathedral felt also like a memorial for Washington herself — a capital city that under President Donald Trump no longer seems capable, as the late senator was, of balancing fights with friendships, of divorcing disagreement from disrespect, of recognizing the basic difference between opponents and enemies.