That would be 1976, when all 153 fourth-year cadets were expelled. I guess we're all enlightened now. From the article: "Nearly all of those who admitted guilt have been allowed to remain at the academy on the condition that they complete a rehabilitation program that includes meeting with a mentor and after-hours classes about the honor system and the importance of being a better leader..."
A "rehabilitation program". Not only should these cadets be expelled, but so should the clowns running this program.