But underneath the sometimes silly enactment of the disavowal ritual there lies a worthwhile search for understanding. We’re talking about the people who would be president, and even though we know a good deal about them, it’s important to know who they’ll surround themselves with, even if they can’t be responsible for everyone who tries to attach themselves to the candidate or the president. When they assume office, presidents carry with them an enormous constellation of people. There’s the staff, of which there are thousands throughout the federal government. There are the political allies inside government, particularly members of Congress. Then there are the interest groups, the lobbyists, the supporters, and everyone else who might exercise some influence over the person in the Oval Office. There are those who offer their private counsel and those who agitate from without. We should try to understand as best we can who all those people are, and how much sway they might have.

Disavowals don’t usually enable us to do that, since they tend to focus on the outliers, not those who are likely to be close to the president. I seriously doubt that even if Donald Trump were president and American society plunged into a harrowing post-apocalyptic nightmare of madness, chaos, and despair, that David Duke would be able to call up the White House and get Trump on the phone.

So why do we insist that Trump disavow Duke? If Duke endorsed Hillary Clinton, she would just say, “That’s bizarre,” and no one would demand a disavowal. That’s because no one believes that David Duke has anything to do with her views or what kind of president she’d be. But it’s precisely because Trump has based so much of his campaign on ugly nationalism that when Duke offers his endorsement, we actually have to ask Trump to be clear.