their original ideology. The conference increased divisions within the Weather Underground. East coast members favored a commitment to violence and challenged commitments of old leaders, Bernardine Dohrn, Bill Ayers, and Jeff Jones. These older members found they were no longer liable for federal prosecution because of illegal wire taps and the government's unwillingness to reveal sources and methods favored a strategy of inversion where they would be above ground "revolutionary leaders". Jeremy Varon argues that by 1977 the WUO had disbanded. Matthew Steen appeared on the lead segment of CBS's 60 Minutes in 1976 and was interviewed by Mike Wallace about the ease of creating fake identification, the first ex-Weatherman interview on national television. (The House document has the date wrong, it aired February 1, 1976 and the title was Fake ID.) The federal government estimated that only 38 Weathermen had gone underground in 1970, though the estimates varied widely, according to a variety of official and unofficial sources, as between 50 and 600 members. Most modern sources lean towards a much larger number than the FBI reference. An FBI estimate in 1976, or slightly later, of then current membership was down to 30 or fewer. Plot to bomb office of California Senator In November 1977, five WUO members were arrested on conspiracy to bomb the office of California State Senator John Briggs. It was later revealed that the Revolutionary Committee and PFOC had been infiltrated by the FBI for almost six years. FBI agents Richard J. Gianotti and William D. Reagan lost their cover in November when federal judges needed their testimony to issue warrants for the arrest of Clayton Van Lydegraf and four Weather people. The arrests were the results of the infiltration. WUO members Judith Bissell, Thomas Justesen, Leslie Mullin, and Marc Curtis pleaded guilty while Van Lydegraf, who helped write the 1974 Prairie Fire Manifesto, went to trial. Within two years, many members turned themselves in after taking advantage of President Jimmy Carter's amnesty for draft dodgers. Mark Rudd turned himself in to authorities on January 20, 1978. Rudd was fined $4,000 and received two years' probation. Bernardine Dohrn and Bill Ayers turned themselves in on December 3, 1980, in New York, with substantial media coverage. Charges were dropped for Ayers. Dohrn received three years' probation and a $15,000 fine. Brinks robbery Some members remained underground and joined splinter radical groups. The U.S. government states that