Following the end of the Second World War, Yugoslavia became a socialist state following the success of the Yugoslav Partisans in their resistance of the Axis powers. In 1948, following the Tito–Stalin split, Yugoslavia broke ties with the Soviet Union and its allies. During the Cold War, it was one of the leading members of the Non-Aligned Movement. After the Soviet Invasion of Czechoslovakia in 1968, the concerns about an eventual Soviet attack started to rise within the Yugoslav leadership. The invasion of Czechoslovakia showed that the standing conventional forces of a small country could not repulse a surprise attack by a qualitatively and quantitatively superior aggressor. Being strategically positioned between the two major blocs, the NATO and the Warsaw Pact, Yugoslavia had to prepare its own military doctrine for a potential mass invasion scenario.