Ku Klux Klan as a Fraternity honor society.
 

During the first quarter of the 20th century, University of Illinois had an Honor society for Juniors in Social Fraternities (apparently at one point limited to one per fraternity) called Ku Klux Klan. I noticed it doing research on fraternities in the 1920s at U of Illinois. Apparently they had chapters at at least 5 schools (including U of Wisconsin) In 1923 they changed their name to Tu-mas and later went inactive in the 1930s.

See https://archives.library.illinois.ed...s/kluklux.html

During the 1920s, in parts of the U.S., including Oklahoma, the Klan was a very popular organization, boasting massive membership roles. We had a period in the 20s in Oklahoma where the Klan basically ran the State government. Following the 1921 race riots in Tulsa, after the Governor declared martial law, the Klan-influenced legislature had him impeached and removed from office. Reportedly, I had a great-great grandfather who was a member. Family said he resigned after the more nefarious aspects of the Klan became known, but I'm skeptical that such willful ignorance could possibly have existed.