Donald Trump and Joe Biden come into Thursday’s presidential debate as incredibly well-known quantities defined by shared unpopularity and competing weaknesses. But their most important liabilities — for the incumbent, his decrepitude and his record on inflation; for the challenger, an unfitness distilled and confirmed by the events of Jan. 6 — feel too well known to be worth discussing further until we see what happens on the stage. Maybe Biden’s entire campaign will implode when he answers a question about inflation with a Grandpa Simpson ramble about the price of a frozen custard on Rehoboth Beach in 1968. Maybe Trump will turn into Colonel Jessep under Jake Tapper’s questioning and claim full responsibility for the 2021 riot at the Capitol. But before the two men meet with those or other destinies, it’s worth giving some space to their crucial secondary weaknesses, the places where each candidate’s support might be undermined among those “double-hater” voters who regard each candidate’s primary liabilities as canceling the other’s out.

---

Persons: Donald Trump, Joe Biden, Grandpa Simpson ramble, Trump, Jessep, Jake Tapper’s Locations: Rehoboth Beach