Second, Johnson was forward looking. He ran as the candidate of Brexit — not, as Theresa May had, as its reluctant and dutiful custodian, but as its persevering and happy warrior. Brexit wasn’t just about unyoking the U.K. from the E.U. It was also a statement of British self-belief, self-reliance and capacity for self-rule.

That meant that the moment Brexit passed, it was both morally wrong and politically dumb to try to reverse the result. The former, because it was an attempt to nullify people’s votes. The latter, because it could only be accomplished by means of complex parliamentary and legalistic maneuvers to get a second referendum — carried out by the people who always claim to know what’s true and right.

If impeachment — which I support as a matter of constitutional duty but fear on political grounds — winds up helping Trump get re-elected, it will be for similar reasons. That is, Democrats got so wrapped up in trying to bring the president down by legal and legislative means that they forgot to bring him down by ordinary political ones. The main job of any competent opposition is to fight the next election, not relitigate the past.