On Sunday, CNN’s Jake Tapper asked Trump whether he’d repudiate the support of David Duke, the former Grand Wizard of the Knights of the Ku Klux Klan, or “other white supremacists.” Trump evaded the question:

Donald Trump: Well, I have to look at the group. I mean, I don’t know what group you’re talking about. You wouldn’t want me to condemn a group that I know nothing about. I’d have to look. If you would send me a list of the groups, I will do research on them, and certainly I would disavow if I thought that there was something wrong. Jake Tapper: The Ku Klux Klan… Trump: But you may have some groups in there that are totally fine, and it would be very unfair. So, give me a list of groups and I’ll let you know. Tapper: Okay, I’m just talking about David Duke and the Ku Klux Klan here but… Trump: Honestly, I don’t know David Duke. I don’t believe I’ve ever met him. I’m pretty sure I didn’t meet him, and I just don’t know anything about him.

In 2000, Trump was unambiguous about condemning the intolerance of the Reform Party, because it “now includes a Klansman, Mr. Duke, a neo-Nazi, Mr. Buchanan, and a communist, Ms. Fulani,” he said. “This is not company I wish to keep.'' On Friday, Trump was asked about Duke’s support, and replied, “I disavow him, OK?” But somehow, by Sunday, he’d forgotten both who Duke was, and how repellent his ideology is.

Most historians separate the Klan into three distinct movements. The first was a terrorist insurgency that flourished after the Civil War. The third was active in the civil-rights era, and is the direct progenitor of Duke’s group and other Klan factions that are still active today. Both of those groups were most active in the former Confederate states, and made the violent enforcement of inequality and segregation their primary aim. The second Klan, though, was something else. In the 1920s, it enrolled millions of members, crusading for the restoration of a white, Christian, Protestant America—targeting Catholics and Jews as well as blacks, and enjoying particular popularity in the lower Midwest.