The logical presidential playbook would be to tout his accomplishments: Brag about nominating three conservative justices to the Supreme Court. Remind voters that he succeeded in diminishing ISIS while taking out the head of Iran’s notorious Revolutionary Guard. Argue that the economy is slowly but surely getting back on track. Envision a future where a coronavirus vaccine finally restores some sense of normalcy to a psychologically battered country. And in between, throw some pointed jabs at Joe Biden for not speaking out against the ideological excesses of his party’s base.

Trump did little of that. Instead, he sounded downright unhinged at times, vitriolically lashing out against the former vice president and constantly speaking over his opponent. The behind-the-scenes ugliness that’s been documented in countless first-person accounts of the president’s behavior was on display for tens of millions of Americans to see. Is it plausible that any of the remaining persuadable voters watched last night’s debate and decided that they want another four years of this?

Holding a lead, Biden simply needed to show up and make a coherent argument for why he’s an acceptable alternative. In that sense, he won by default. Despite struggling to get in a word at times, he laid out the case for his campaign while getting in a few jabs of his own at the president. “Will you just shut up, man? This is so unpresidential,” Biden said at one point, in what qualified as one of the few memorable lines in the 90-minute affair.