Complex sentence: He was made Assistant Secretary of State for Far Eastern Affairs in 1950 and played an influential part in the US decision to become involved in the Korean War, and also in Japan's postwar compensation for victorious countries, such as the Rusk documents.
Split into simpler sentences: He was made Assistant Secretary of State for Far Eastern Affairs in 1950. He played an influential part in the US decision to become involved in the Korean War, and in Japan's postwar compensation for victorious countries, such as the Rusk documents.