John Joseph Mearsheimer (1947) is an American political scientist and international relations scholar, who belongs to the realist school of thought. He is the R. Wendell Harrison Distinguished Service Professor at the University of Chicago. He has been described as the most influential realist of his generation.
Mearsheimer is best known for developing the theory of offensive realism, which describes the interaction between great powers as being primarily driven by the rational desire to achieve regional hegemony in an anarchic international system. In accordance with his theory, Mearsheimer believes that China's growing power will likely bring it into conflict with the United States.
Mearsheimer's works are widely read and debated by 21st-century students of international relations. A 2017 survey of US international relations faculty ranks him third among "scholars whose work has had the greatest influence on the field of IR in the past 20 years.