Now a key participant in the Columbia rebellion has made a startling confession. Mark Rudd, who was chairman of the SDS chapter during the disturbances, acknowledges that a fellow radical, John "J.J." Jacobs, set the fire in Hamilton Hall, and that he, Rudd, went along with the plan. The confession, a depressing postscript to the 1960s, solves a four-decade-long mystery. It offers a grim testament to just how mean things got at Columbia, and a sobering reminder that not all student radicals were starry-eyed idealists. In more than a couple of cases, they were power-hungry extremists jostling for control of the student-protest movement. And Ranum had the audacity to get in their way.