Summary The article analyses the extensive and passionate responses that the American Civil War and the issues it raised elicited from John Stuart Mill. While it attempts to offer a brief but comprehensive overall account of Mill's influential involvement in debates on the Civil War both in Britain and in America, it focuses particularly on Mill's defence of racial equality for the American ?negroes? both during the war and in the course of debates on reconstruction after the war. Mill's concerted (...) efforts to contribute to the improvement of Anglo-American relations and to influence both British public opinion and how that opinion was viewed from America are also analysed. Detailed attention is paid to Mill's strong views on reconstruction, which have not received the attention they deserve. A number of Mill's views and ?crotchets? were tested in the debates on reconstruction, and, whenever he had to choose between conflicting principles, his uncompromising hatred of slavery and racial inequality took priority over any other considerations (even ones as important as educational qualifications for voters, and free trade). (shrink)