Arthur Meier Schlesinger, Jr., born Arthur Bancroft Schlesinger (October 15 1917 - February 28 2007), was a Pulitzer Prize recipient and American historian and social critic whose work explored the liberalism of American political leaders including Franklin D. Roosevelt, John F. Kennedy, and Robert F. Kennedy. He served as special assistant and "court historian"r=1&oref=slogin" target="_blank">http://www.nytimes.com/2007/03/04/weekinreview/04tanenhaus.html?_r=1&oref=slogin to the President in John F. Kennedy's administration. He wrote a detailed account of the Kennedy administration, titled A Thousand Days.

During the deliberations of the United States decision to invade Cuba at the Bay of Pigs, with President Kennedy and his closest advisers, he was one of two persons who opposed the strike (the other being _William Fulbright); however, he sat silent, except writing a private memorandum to President, not wanting to undermine the President's desire for a unanimous decision. Following the overt failure of the invasion, Schlesinger later lamented "In the months after the Bay of Pigs, I bitterly reproached myself for having kept so silent during those crucial discussions in the cabinet room . . . I can only explain my failure to do more than raise a few timid questions by reporting that one's impulse to blow the whistle on this nonsense was simply undone by the circumstances of the discussion." Schlesinger was a prolific contributor to liberal theory and was a passionate and articulate voice for Kennedy-style liberalism. He was admired for his wit, scholarship, and devotion to delineating the history and nature of liberalism. Since 1990 he had been a critic of multiculturalism.

He popularized the term "imperial presidency" during the Nixon administration by writing the book The Imperial Presidency.