Noted political scientist Masamichi Inoki, one-time head of the National Defense Academy and known for his critical views of Marxism, died of natural causes Monday morning, his family said Wednesday. He was 98.

The Kyoto native became a professor at Kyoto University in 1949 and developed a realistic political theory based on liberalism and social democracy while criticizing Marxism for its nature that led to dictatorship in the former Soviet Union.

Inoki, a graduate of the University of Tokyo, studied under wartime liberalist Eijiro Kawai.

He became head of the academy in 1970.