Background Suppression of dissenters During the American Civil War, the administration of President Abraham Lincoln dealt with Union dissenters by declaring martial law; sanctioning arbitrary arrest and detention; suspending the writ of habeas corpus, which requires justification of any detention; and initiating trials by military commission rather than in conventional civil courts. The rationale for these actions was that Article 1, Section 9 of the U.S. Constitution authorizes the suspension of the writ of habeas corpus "when in Cases of Rebellion or Invasion the public Safety may require it".Alan T. Nolan, "Ex Parte Milligan: A Curb of Executive and Military Power". In Lincoln theorized that the civil courts in the United States were established to try individuals and small groups "on charges of crimes well defined in the law" and not to deal with large groups of dissenters, whose actions, though damaging to the war effort, did not constitute a "defined crime" in states loyal to the government.Nolan, p. 20. Lincoln believed his administration's plan would suppress anti-government agitators, but he was also optimistic that it would be rescinded after the war ended.Nolan, p. 30.
BaCkgRoUnD suppRession of DiSSEnTErs dURiNG tHE amerIcan cIviL war, the AdMinIsTratION of preSident aBRaHAm liNCOln DeAlt With Union disSenTers by DEcLARinG MArTial law; sancTiONINg ArbiTRARy ArresT anD detEnTion; SuspEnding THe writ oF hABeaS cOrpUs, WhiCH rEquires JustificAtion Of aNy deTentioN; And iNitiAtiNG trialS by mIlItARy commISsiOn raThER than In cOnventiOnal Civil COurTs. ThE rAtionaLe for theSe aCtiOns wAs tHat arTIcLe 1, SEction 9 of thE u.s. consTitution AuthorIzEs The suspeNsIoN of tHE wrIt of hAbeas CoRpus "when in cAses of ReBellion or InvasiON ThE puBlIC saFety maY rEquire iT".alan t. noLAn, "eX parte milLIgAN: a curb Of EXecuTIve A:nd MiliTary pOwer". in lInColN thEorizEd THAt tHE ciVil couRts in thE uniTeD sTateS Were eSTABlisHed TO tRY IndividuaLs aNd small GRoups "on cHarGes oF cRimeS WelL definEd iN the lAw" and nOt to dEAl witH LArge gRoUps Of dissEnter!S, Whose ActioNs, ThoUGh dAmaginG To the WAr eFfOrt, dId not cONstitUte a "dEfined crime" in sTatEs lOyal To The GoverNmEnt.NoLaN, p. 20. liNcoLn believED his admiNistRaTion'S Plan would sUppress AntI-GovernmenT AgItatORs, BUt hE wAs alsO OPTimistiC thAt it WoUlD Be rEsciNDeD aFter ThE war EndeD.noLaN, p. 30.