Introduction : the genealogical origins of necessity and military necessity -- The capture of Major André -- Cultural amnesias and legal recollections : forgetting and remembering the 1862 U.S.-Dakota war tribunals -- Abraham Lincoln and ex parte Milligan -- The military trial of Major Henry Wirz -- FDR, wartime anxieties, and the Saboteurs' case -- General MacArthur's tribunal and the trial of General Yamashita -- The legal and public debates over the necessity of Bush's military order -- The future use of military tribunals.