In its season opener “Saturday Night Live” did a fine job of skewering political figures who dominated headlines during the show’s summer hiatus. The Trump stuff was funny, but even with new Ukrainian fodder it was routine. The Democratic parodies, however, were fresh and so spot-on that they exposed the frustrating frailties of the 2020 field.

On the GOP side, Alec Baldwin was back as a conniving President Trump and Kate McKinnon nailed her clownish and publicity-thirsty Rudy ...