Ex parte Milligan

Ex parte Milligan

Company type	U.S. Supreme Court case
Industry	Law / Judiciary
Founded	1866
Headquarters	Washington, D.C. , United States
Key people	Justice David Davis (majority opinion), Chief Justice Salmon P. Chase

Ex parte Milligan, 71 U.S. (4 Wall.) 2 (1866), represents a pivotal ruling by the U.S. Supreme Court establishing that civilians cannot be tried by military tribunals when civilian courts remain operational. The Court invalidated the military commission authority employed by former President Abraham Lincoln's administration to prosecute Union opponents during the American Civil War. Justice David Davis, authoring the majority opinion, asserted that "martial rule can never exist when the courts are open," thereby confining martial law to scenarios where civil governance is suspended due to active military operations. While Chief Justice Salmon P. Chase and three associate justices agreed with the verdict, they contended that Congress could authorize military commissions, a power not exercised in this instance.

The controversy originated from the military tribunal trial of Lambdin P. Milligan, Stephen Horsey, William A. Bowles, and Andrew Humphreys held in Indianapolis on October 21, 1864. The defendants were charged with offenses including conspiracy against the federal government, providing aid to the Confederates, and fomenting rebellion. On December 10, 1864, Milligan, Bowles, and Horsey were convicted and sentenced to death by hanging; Humphreys received a sentence of hard labor for the war's duration, later adjusted for conditional release. President Andrew Johnson commuted the death sentences of Milligan, Bowles, and Horsey to life imprisonment. Subsequently, on May 10, 1865, Milligan’s attorney submitted a habeas corpus petition to the Indiana Circuit Court contesting his detention; similar petitions were filed on behalf of Bowles and Horsey. Due to conflicting judicial opinions regarding the legitimacy of military trials for civilians, the matter escalated to the Supreme Court, with arguments presented on March 5 and 13, 1866, and a ruling delivered on April 3, 1866.

Suppression of dissenters

Throughout the American Civil War, President Abraham Lincoln's administration took measures against Union dissenters by imposing martial law, authorizing arbitrary arrest and detention, suspending the writ of habeas corpus, and substituting civil courts with military commissions. This approach was grounded in Article 1, Section 9, which permits suspension of habeas corpus "when in Cases of Rebellion or Invasion the public Safety may require it." Lincoln maintained that civilian courts lacked capacity to manage widespread dissent threatening the war effort. These interventions were intended as temporary wartime measures.

A notable early instance occurred in 1863 with Clement Vallandigham, an anti-war Democrat from Ohio, who was arrested and tried before a military commission. Although sentenced to imprisonment, Lincoln commuted Vallandigham’s punishment and exiled him to Confederate territory. The U.S. Supreme Court declined to hear Vallandigham's appeal.

Trial by military commission

The subsequent significant episode involved trials initiated by General Alvin Peterson Hovey in Indiana during 1864 targeting leaders affiliated with the Sons of Liberty and other anti-war Democrats such as attorney Lambdin P. Milligan and journalist Joseph J. Bingham. Arrests occurred between August and October 1864; while some allegations were dropped, others proceeded to formal trial.

On October 21, 1864, a military commission assembled to try Milligan and his co-defendants on charges including conspiracy against the United States government, supporting Confederate forces, inciting rebellion, engaging in disloyal conduct, and breaching laws of war. Accusations detailed plans to liberate Confederate prisoners from camps in Illinois, Indiana, and Ohio; seize an arsenal; arm freed prisoners; provoke insurrection; and collaborate with Confederate troops to invade Midwestern states.

The verdict rendered on December 10, 1864 found Milligan, Bowles, and Horsey guilty with sentences of death by hanging; Humphreys was condemned to hard labor but subsequently granted conditional freedom under General Hovey’s authority with President Lincoln’s endorsement. Following Lincoln’s assassination, petitions for clemency were directed toward President Andrew Johnson.

Circuit Court petition

On May 10, 1865, Jonathan W. Gorden, representing Milligan as his attorney, submitted a petition for a writ of habeas corpus to the U.S. Circuit Court for the District of Indiana in Indianapolis. Comparable petitions were also filed on behalf of Bowles and Horsey. These filings invoked the Habeas Corpus Suspension Act 1863, which took effect on March 3, 1863, and addressed the constitutional question of whether President Lincoln had the authority under Article 1, Section 9 of the U.S. Constitution to suspend habeas corpus. Milligan's petition highlighted that a federal grand jury convened in Indianapolis in January 1865 had declined to indict him, thereby qualifying him for release under the provisions of the act.

On May 16, just three days before their planned executions, Horsey's death sentence was commuted to life imprisonment, and the executions of Milligan and Bowles were deferred until June 2. Subsequently, on May 30, 1865, President Johnson granted commutations for both Milligan and Bowles to life sentences. Concurrently, Justice David Davis, an associate justice of the U.S. Supreme Court and federal circuit judge for Indiana, together with Judge Thomas Drummond, examined Milligan's petition. They held differing opinions regarding the authority to try civilians by military commission and thus referred the matter to the U.S. Supreme Court.

Arguments

The Supreme Court was tasked with resolving three issues in Ex parte Milligan:

• Whether a writ of habeas corpus should be issued based on Milligan's petition;
• Whether Milligan should be released from custody;
• And whether the military commission had lawful jurisdiction to try and convict Milligan.

The Court’s review was confined exclusively to evaluating the constitutionality of the military tribunal proceedings and Milligan’s right to discharge, without considering the underlying evidence or charges against him.

Oral arguments took place on March 5 and 13, 1866. The United States government’s case was presented by Attorney General James Speed, Henry Stanbery, and General Benjamin F. Butler—a Civil War general who later served as a congressman and governor of Massachusetts—with Butler delivering the primary argument. Representing Milligan were Joseph E. McDonald; New York attorney David Dudley Field; Congressman James A. Garfield in his initial courtroom appearance who would later become president; and Jeremiah S. Black, former Attorney General and Secretary of State under President Buchanan.

Decision

On April 3, 1866, Chief Justice Salmon P. Chase ruled that under the congressional act of March 3, 1863, a writ of habeas corpus could indeed be issued; that the military commission lacked jurisdiction over Milligan; and that he was entitled to release. Milligan, Bowles, and Horsey were subsequently freed on April 12, 1866. The Court’s opinion was formally read at its next session.

Justice Davis delivered the majority opinion on December 17, 1866, underscoring that as a civilian residing in a state with operational courts, Milligan was entitled to trial under civilian judicial procedures. This encompassed protections such as safeguards against unreasonable searches and seizures, warrants grounded in probable cause, and prompt jury trials. Davis dismissed the federal government’s rationale for military commissions by asserting that "martial rule can never exist when the courts are open," confining martial law strictly to active war zones where civil authority has been displaced—circumstances absent in Indiana at the time of Milligan’s arrest and trial. The opinion clarified that even during habeas corpus suspension citizens may be detained without formal charges but cannot be subjected to trial or execution by military tribunals. It emphasized that habeas corpus is a procedural tool to enforce rights rather than a right itself.

In this landmark ruling concerning governmental power versus individual liberties, Ex parte Milligan firmly upheld personal rights against undue expansion of military jurisdiction. It curtailed President Lincoln’s administration from broadening military commission authority and thus guarded against potential future abuses. Politically, amid a post-Civil War Republican-controlled Congress, the Court refrained from undermining military courts’ legitimacy in occupied Southern states. The case did not directly confront presidential habeas corpus suspension powers since Congress had already authorized such suspension in 1863; Milligan’s detention occurred subsequent to this legislative endorsement.

Chief Justice Chase acknowledged that although courts existed in the South, they might be ineffective against threats or conspirators—highlighting concerns about state courts’ capacity to protect freed slaves from violence during Reconstruction.

Categories of Military Jurisdiction

This ruling clarified the extent of military jurisdiction as defined by the U.S. Constitution. The Supreme Court outlined three distinct categories:

1. Authority exercised during both peace and wartime under MILITARY LAW, which is regulated by congressional statutes establishing rules and articles of war for national armed forces;

2. Jurisdiction in foreign conflicts or rebellions over occupied regions under MILITARY GOVERNMENT, administered by military officials with approval from the President and Congress;

3. MARTIAL LAW PROPER, declared in cases of invasion, rebellion, or civil war within loyal states when public safety necessitates the suspension of ordinary legal processes, authorized by either Congress or the President during emergencies.

Prior to 1866, differentiating between martial law and military government was relatively rare but has since become a fundamental legal distinction. Birkhimer’s 1914 publication Military Government and Martial Law clarifies: "Military Government operates over enemy-held territory; Martial Law applies to loyal territory." Military government is governed by international law as part of wartime regulations, while martial law is subject to domestic legal frameworks.

According to the U.S. Army Field Manual FM 27-10, The Law of Land Warfare, military government entails governance by an occupying force over areas where the legitimate civil authority is unable to function due to occupation or security issues. The manual further differentiates military government as relevant to hostile or previously hostile lands under international law restrictions, whereas martial law pertains exclusively to domestic regions not recognized as belligerents and is controlled by U.S. domestic statutes.

Separate Opinion

Justices David Davis along with Nathan Clifford, Stephen Johnson Field, Robert Cooper Grier, and Samuel Nelson joined the majority opinion. Meanwhile, Chief Justice Salmon P. Chase and Justices James Moore Wayne, Noah Haynes Swayne, and Samuel Freeman Miller issued a concurring opinion agreeing with the judgment but disputing the conclusion that Congress lacked authority to establish military commissions in Indiana. Chief Justice Chase maintained that Congress possessed such authority but had not exercised it in Milligan’s situation. Their opinion asserted that Congress could "authorize trials for offenses against the security and safety of national forces," basing this power on its constitutional rights to raise armies and declare war, even if civilian courts were operational but insufficiently prompt to counter threats. Nevertheless, as Justice Davis emphasized, the Indiana Circuit Court "required no bayonets for protection nor any military assistance to enforce its rulings".

Aftermath

Ex parte Milligan stands as a pivotal decision by the U.S. Supreme Court that curtailed presidential authority during armed conflict, affirming that both military and executive powers must operate within constitutional limits.

Following his release, Milligan returned to practicing law in Huntington, Indiana. In 1868, he initiated a civil suit in Huntington County, Indiana seeking compensation connected to the Ex parte Milligan case. The lawsuit, known as Milligan v. Hovey, was heard in May 1871 before the U.S. Circuit Court in Indianapolis. Defendants included Alvin P. Hovey and Oliver P. Morton. Milligan was represented by Thomas A. Hendricks, while the defense enlisted future President Benjamin Harrison. This trial is notable as one of the earliest significant federal civil rights jury trials. Harrison depicted Milligan as a traitor, whereas Hendricks argued that Milligan had been subjected to malicious prosecution and unlawful imprisonment. During the proceedings, Milligan refuted any association with seditious factions. On May 30, 1871, the jury decided in favor of Milligan. Although he pursued substantial damages, prevailing laws restricted his recovery to five dollars plus court costs.

See also

• Ex parte Merryman (C.C.D. Md. 1861)
• Ex parte Quirin (1942)
• Hamdi v. Rumsfeld (2004)
• List of United States Supreme Court cases, volume 71
• Martial law
• Supreme Court cases of the American Civil War

References

• "The Law of Land Warfare." In (Subscription needed) (This manual supersedes FM 27-10, 1 October 1940, including C 1, 15 November 1944. Changes required on 15 July 1976 have been incorporated within this document.)
• Nolan, Alan T., "Ex Parte Milligan: A Curb of Executive and Military Power." In

Further reading

• Coleman, Elisheva Ruth (2005). "Call It Peace or Call It Treason: The Milligan Case and the Meaning of Loyalty in the Civil War." Princeton, NJ: Princeton University.
• Neely Jr., Mark E. (1991). The Fate of Liberty: Abraham Lincoln and Civil Liberties. New York: Oxford University Press.
• Pitman, Benn (1865). The Trials for Treason at Indianapolis, Disclosing the Plans for Establishing a North-Western Confederacy. Cincinnati: Moore, Wilstach and Baldwin.
• Rehnquist, William H. (1998). All the Laws but One: Civil Liberties in Wartime. New York: William Morrow and Co.
• Stampp, Kenneth M. (June 1944). "The Milligan Case and the Election of 1864 in Indiana". Mississippi Valley Historical Review. 31 (1): 41–58.
• Winger, Stewart L., and White, Jonathan W., eds. (2020). Ex Parte Milligan Reconsidered: Race and Civil Liberties From the Lincoln Administration to the War on Terror. Lawrence, Kansas: University of Kansas Press.