According to Bill Ayers in the late 1970s, the Weatherman group further split into two factions—the May 19th Communist Organization and the Prairie Fire Collective—with Bernardine Dohrn and Bill Ayers in the latter. The Prairie Fire Collective favored coming out of hiding and establishing an above-ground revolutionary mass movement. With most WUO members facing the limited criminal charges (most charges had been dropped by the government in 1973) against them creating an above ground organization was more feasible. The May 19 Communist Organization continued in hiding as the clandestine organization. A decisive factor in Dohrn's coming out of hiding were her concerns about her children. The Prairie Fire Collective faction started to surrender to the authorities from the late 1970s to the early 1980s. The remaining Weather Underground members continued to attack U.S. institutions.