By definition, everything a president does is, to his critics, bad public policy. If Mr. Trump had no business interests, his opponents would still see his policies as self-interested attempts to curry favor with some particular voting bloc, donor group, logrolling legislation faction, future benefactors of his presidential library, or journalists and biographers whom he hopes will pen glowing tributes.

In what sense, then, are his business conflicts a meaningful complication of the necessary suspicion that follows all presidential actions?

Mr. Trump, with his forthcoming Dec. 15 press conference, promises a “solution.” Reason tells us any solution can only be ceremonial. If he transfers control to his children, he will still own a big stake in the Trump business. If he sells out to his children entirely, he will still care about their future success.

If he dismantles the business, disinherits his children and retires the Trump brand (which he would never do, since the cost would be extravagant), he would still wake up to find his every action assailed by opponents.