Lech Wałęsa and others formed a broad anti-Soviet social movement ranging from people associated with the Catholic Church to members of the anti-Soviet left. Polish nationalism, together with pro-American liberalism, played an important part in the development of Solidarity in the 1980s. Solidarity advocated non-violence in its members' activities. In September 1981, Solidarity's first national congress elected Wałęsa as a president and adopted a republican program, the "Self-governing Republic". The government attempted to destroy the union with the martial law of 1981 and several years of repression, but in the end it had to start negotiating with the union.