Complex sentence: In foreign policy, in contrast with his 1970s Latin American contemporaries, which were mostly right-wing military dictatorships, he pursued a partnership with the Soviet bloc, tightening relations with Cuba and Fidel Castro and undertaking major purchases of Soviet military hardware.
Split into simpler sentences: In foreign policy, in contrast with his 1970s Latin American contemporaries, which were mostly right-wing military dictatorships, he pursued a partnership with the Soviet bloc. He tightened relations with Cuba and Fidel Castro and undertook major purchases of Soviet military hardware.