Soviet foreign policy was revised, and Litvinov was replaced as foreign minister in early May 1939 to facilitate the negotiations that led to the Molotov–Ribbentrop Pact with Germany, which was signed by Litvinov's successor, Vyacheslav Molotov, on August 23. The war in Europe broke out a week later with the invasion of Poland, which started on September 1. Thus, collective security may not always work because of the lack of commitment and the unwillingness of states or the international community to act in concert (Mingst 1999).
