The political realignment allowed House leaders to alter rules that had allowed Southern Democrats to kill New Frontier and civil rights legislation in committee, which aided efforts to pass Great Society legislation. In 1965, the first session of the Eighty-Ninth Congress created the core of the Great Society. It began by enacting long-stalled legislation such as Medicare and federal aid to education and then moved into other areas, including high-speed mass transit, rental supplements, truth in packaging, environmental safety legislation, new provisions for mental health facilities, the Teacher Corps, manpower training, the Head Start program, aid to urban mass transit, a demonstration cities program, a housing act that included rental subsidies, and an act for higher education. The Johnson Administration submitted 87 bills to Congress, and Johnson signed 84, or 96%, arguably the most successful legislative agenda in US congressional history