Robert Green McCloskey (8 January 1916 – 4 August 1969) was an American political historian.

Robert McCloskey originally studied at the University of Wisconsin, receiving an AB,^[1] eventually completing his doctorate in political science at Harvard University, whose faculty he joined in 1948.^[2] He was secretary of the Littauer Center of Public Administration until 1954, when Arthur Maass took the position.^[3] He became an associate professor at the university in 1953, eventually settling as Professor of Government in 1958.^[1]

McCloskey was awarded a Guggenheim Fellowship in 1959.^[4] His book The American Supreme Court was the winner of the 1961 Award of the Contemporary Affairs Society.^[1] In 1966, McCloskey was named Jonathan Trumbull Professor of American History and Government at Harvard. The position had been vacant since 1963, upon the death of V. O. Key.^[5] McCloskey died on 4 August 1969.^[6][7]

McCloskey's book American Conservatism in the Age of Enterprise was first published in 1951. The book was based on his doctoral dissertation,^[8] and explored conservatism in the United States from the Reconstruction era to 1910, by considering the publications of William Graham Sumner, Stephen Johnson Field, and Andrew Carnegie.^[9][10] The first edition of The American Supreme Court was published in 1961 as part of a series,^[11] and described as "lucidly written, well-reasoned, and concise" by Robert J. Harris,^[12] and "one of the best of a rare breed" by Paul W. Fox.^[13] In 2011, Keith E. Whittington called it "the classic one-volume history of the Court."^[14]

Robert McCloskey married Helen Stueland, with who he had 3 children (including economist Deirdre McCloskey) before dying at the Peter Bent Bridhamn Hospital (now part of the Brigham and Women's Hospital) in August 1969.^[1] Following his death, a student of McCloskey's, Sanford Levinson, continued updating The American Supreme Court.^[15] A third book by McCloskey, titled The Modern Supreme Court, was posthumously published in 1974.^[16]