President Trump made a big unforced error attacking DeSantis at his rally the other day. Not just because he did so just before an election day on which the Republicans simply must destroy the Democrats–after all, Governor DeSantis doesn’t need Trump’s support to win. If Trump went into full attack mode it wouldn’t dent DeSantis’ reputation one little bit. So Trump’s attack is electorally irrelevant (which in itself is an unforced error, as it shows Trump to be weaker than he wants to look against a political rival). Trump’s attack was a mistake because he opened up an old wound...