Lambdin Milligan, an Indiana civilian, was tried by military commission during the Civil War and sentenced to hang. The Supreme Court unanimously ordered him freed. Justice Davis wrote that the Constitution 'is a law for rulers and people, equally in war and in peace' and that martial law cannot supplant civilian courts when those courts remain open and functioning. Milligan is a foundational check on executive war power and was repeatedly invoked against the Bush administration's post-9/11 military-commission policies.