There’s an old political saying that presidential candidates appeal to their parties’ wings — left for Democrats, right for Republicans — in the race for the nomination and then appeal to the center in the general election campaign. It was put in canonical form by Richard Nixon, one of only two Americans that our major parties nominated for national office five times (the other was Franklin Roosevelt).

The dozen or so already-announced Democratic candidates seem to be following Nixon’s rule but with more reckless abandon than Nixon ever did. Maybe they figure that whoever gets the Democratic nomination will inevitably beat President Trump. After all, no one they ever talk to would vote for him.