Ex parte Merryman

Federal Trials and Great Debates 

in United States History

Case Summary:

• Ex parte Merryman was a habeas corpus case challenging the military detention of John 

Merryman, a civilian accused of treason during the U.S. Civil War.

• Chief Justice Roger Taney determined that the Lincoln administration’s policy empowering the 

military to arrest and detain disloyal individuals violated the U.S. Constitution.

• The case is regarded as an important milestone in the evolution of habeas corpus law.

History of the Case:

From the outset of the U.S. Civil War (1861-1865), President Abraham Lincoln was concerned that the 

Union cause could be undermined by Confederate sympathizers in the north. This threat was particularly 

strong in Maryland, a slave state that bordered Confederate Virginia and surrounded Washington, D.C. 

on three sides. Lincoln believed the unique nature of the Civil War called for drastic measures to ensure 

victory and worried that ordinary criminal processes would not be sufficiently quick or reliable to deal with 

the peril. In 1861, he authorized Winfield Scott, the commanding officer of the Union Army, to suspend 

the writ of habeas corpus anywhere between Philadelphia and Washington, D.C. and empowered military 

officers to arrest and detain suspected Confederate sympathizers.

On May 25, 1861, Union soldiers arrested John Merryman, a wealthy farmer believed to hold 

secessionist views, and held him at Fort McHenry near Baltimore on the grounds that he had interfered 

with Union troop movements. Merryman’s attorney petitioned Chief Justice Roger Taney, who served as 

the circuit justice for the U.S. Circuit Court for the District of Maryland, for a writ of habeas corpus. 

Habeas corpus is a longstanding and flexible legal instrument for challenging an individual’s detention. It 

requires the authority holding a prisoner to bring him or her before the court and provide the legal basis 

for the detention. If that basis is insufficient, the court can order the prisoner’s release.

A native Marylander, Taney had been Chief Justice of the United States for twenty-five years and 

stayed on the Union side during the Civil War. Nonetheless, many of his critics believed he too 

sympathized with the rebellion in part because he had written an infamous opinion in Scott v. Sanford 

(1857), which limited Congress’s ability to restrict the spread of slavery and held that African Americans 

had “no rights which the white man was bound to respect.” The day after Merryman’s arrest, Taney 

ordered General George Cadwalader, the officer holding Merryman in custody, to appear before him. 

Cadwalader refused on the grounds that President Lincoln had authorized the suspension of the writ of 

habeas corpus and requested a delay so he could receive further instructions from the President. Taney 

then issued a writ commanding Cadwalader to appear and explain why he should not be held in contempt 

of court, but soldiers at the Fort refused to receive the writ. 

On May 28th, Taney ruled that the President did not have the power to suspend the writ and could 

not usurp the role of the judiciary to determine the guilt or innocence of criminal suspects. Taney 

subsequently released a written opinion detailing the reasoning behind his denial of the President’s 

authority. Taney did not order Merryman’s release, but instead sent a copy of the opinion to Lincoln so 

the President could determine how best to follow his ruling.

Taney’s opinion, which was reprinted in newspapers around the country, issued a sharp rebuke 

to the President and a defense of the judiciary’s independence from the other branches of government. In 

his zeal to suppress a northern rebellion, Taney argued, Lincoln had effectively assumed the powers of all 

three branches of government. Reasoning that the clause permitting the suspension of the writ of habeas 

corpus “in cases of rebellion or invasion” appeared in Article I, the part of the Constitution setting out
Congress’ powers, Taney held that only Congress could suspend the writ. Moreover, because Lincoln 

had authorized the military to determine who had committed treason and similar offenses and to imprison 

them without a trial, Taney contended Lincoln had also improperly taken powers that rightfully belonged 

to the federal judiciary. Although some of Taney’s critics in the north argued that he had overreached his 

own power, many lawyers (including Cadwalader’s own brother, who was a federal judge in Philadelphia) 

concurred with Taney’s legal reasoning and his defense of the importance of both the writ of habeas 

corpus and judicial independence. 

Lincoln continued to insist that he had the power, as President and commander in chief during a 

time of national emergency, to suspend the writ. Congress ratified this position in 1863 by passing a law 

explicitly granting him that authority. In the interim, however, Merryman was indicted in the circuit court for

attempting to levy war against the United States and sabotaging railroads in Maryland. He was released 

on bail, but never stood trial. Taney, who as circuit justice would have presided over the trial, issued a 

continuance delaying the start of proceedings and then fell ill, eventually dying in 1864 without having 

heard the case. In 1867, after the war’s conclusion, a federal prosecutor signed an order announcing that 

the government would not prosecute the case further.

Merryman had a broader legacy than the prosecution of one man, however. Although the full 

Supreme Court never ruled on the case, it served as an important precedent in landmark decisions

following the Civil War and during the recent War on Terror that established the right of civilians to 

challenge their detention by military authorities. It also stands as unusual but significant defense of 

judicial independence and the separation of powers during times of national crisis.

Legal Issues:

• Did the President have the power to suspend the writ of habeas corpus during the Civil War?

• Did the military’s arrest and detention of Merryman violate his rights to a criminal trial?

• Did the President violate the principle of separation of powers by authorizing the military to 

suspend the writ and detain disloyal individuals?

Questions for Discussion:

• Lincoln argued that he needed to be able to suspend the writ of habeas corpus because of the 

emergency created by the Civil War. What unusual aspects of the Civil War might support this 

claim? Should the Constitution be interpreted differently during times of war or other crises?

• Did the Lincoln administration’s response to Chief Justice Taney’s ruling respect the rule of law? 

Could Lincoln have insisted that Merryman never be tried on the grounds that Taney’s decision 

was incorrect and the President has a duty to enforce the law as he interprets it? 

• This case seems somewhat unusual today because Taney was sitting on a “lower” court, a 

practice known as “circuit riding,” which was abolished in 1911. Would it have made a difference 

if a non-Supreme-Court judge had issued the ruling in Merryman’s favor? Would Lincoln have 

been obligated to follow conflicting rulings in different lower courts?

• Taney’s opinion did not address whether Merryman had actually committed the crimes of which 

was accused. Would your view of this case change if you knew whether Merryman was guilty or 

innocent?