Donald Trump is now only the third US president in 230 years to have been impeached, the first to suffer that humiliation in his first term, and the first to have it happen while he is running for re-election. And it couldn’t have happened to a nicer guy.

Trump may well go on to win a second term, which will be a sorry comment on the state of the American republic and the gullibility of the American electorate. If that…