Nobody has yet proved that the president has committed clearly impeachable offenses. The president, however, should spare the nation the systemic upheaval that continuing investigations will catalyze. For the nation’s good, he should follow Richard Nixon’s example, and resign.

Just more than 20 years ago, that was the essence of what I wrote in a column directed at Bill Clinton: There was a “stain on the presidency” that was “public, and embarrassing, and tawdry. And it makes America look cheap and base and trashy. The worst part is, the stain may be the least of the problems. Underneath it is a rot that’s eating away at the fabric.”