Believing that the Confederate states of the South had the power under the U.S. Constitution to secede from the Union, Milligan opposed the war to reunite the nation.

He returned home and practiced law in Huntington, Indiana, where he later filed a civil suit claiming damages for the military arrest and trial.

On May 30, 1871, the jury found in Milligan's favor, but federal and state statutes limited the award for damages to five dollars (~$113.00 in 2023) plus court costs.

Milligan, who was of Irish descent, was born on a farm near Saint Clairsville, in Kirkwood Township, Belmont County, Ohio.

Milligan's father wanted him to attend college to study medicine, but his mother disagreed, insisting that if none of their other children could pursue high education, then neither should seventeen-year-old Lambdin.

Three years later, on August 12, 1873, Milligan married Maria L. (née Humphreys) Cavender,[3] a widow who was a native of Madison, Indiana.

As a young man, he took a prominent role in Belmont County Democratic Party affairs in defense of Jeffersonian states-rights positions.

During the Nullification Crisis of the early 1830s, he echoed South Carolinian John C. Calhoun's stance that the states could "nullify" offensive federal laws.

Resuming his law practice after a hiatus of real estate speculation and holding county positions, he developed a solid reputation as a successful lawyer, mostly representing small railroad companies.

Douglas was found guilty of violating a military order that banned criticism of the Lincoln administration's conduct of the war, but was released after Indiana's Republican governor, Oliver P. Morton, lobbied the president and his cabinet.

Milligan's final courtroom speech in Douglas's behalf was circulated in the local Democratic newspapers, increasing the lawyer's notoriety.

Harrison H. Dodd, "grand commander" of the Order in Indiana, chose several men, including Milligan, to assist him, but this was not known to the group's rank-and-file members.

[7] By the end of 1863 military authorities in Indianapolis believed that Milligan was involved in a conspiracy against the United States and sent army detectives to observe his actions.

[1][4] During the spring and summer of 1864, Milligan continued to oppose the Lincoln administration, arguing that the president's efforts to coerce the southern rebels were unconstitutional.

[1] In May 1864 Federal authorities obtained evidence that Milligan was active in conspiracy to obstruct the war effort and to raise rebellion in Indiana.

[4] On August 13, 1864, Milligan addressed a public meeting at Fort Wayne, Indiana, calling on Democrats to rise up in arms to fight for "liberty, order and peace."

The commission considered five charges:[14][15] The defendants were accused of establishing a secret organization that planned to liberate Confederate prisoners from Union prisoner-of-war camps in Illinois, Indiana, and Ohio; steal weapons from an arsenal; raise an armed force to incite a general insurrection; and join with the Confederates to invade Indiana, Illinois, and Kentucky and make war on the U.S.

In addition, they suggest that the trials, which were highly publicized in the press, were prompted by partisan politics, convened before commission of biased military officers, failed to follow the rules of evidence, and used questionable informers as witnesses.

Efforts were made to secure pardons for Milligan, Bowles, and Horsey, with the decision passing to President Andrew Johnson following Lincoln's assassination.

Circuit Court for the District of Indiana at Indianapolis for a writ of habeas corpus, which called for a justification of Milligan's arrest.

Milligan's petition alleged that a federal grand jury had met in Indianapolis during January 1865, which it did, and it had not indicted him, which is also true, making him eligible for a release from prison under the Habeas Corpus Suspension Act (1863).

[30] Milligan's representatives included James A. Garfield, a member of Congress and a future U.S. president; Jeremiah S. Black, President James Buchanan's U.S. Attorney General and U.S. Secretary of State; David Dudley Field, a New York lawyer and brother of U.S. Supreme Court justice Stephen Johnson Field; and Joseph E.

[34] After Milligan's release from prison, he returned to his home and law practice in Huntington, Indiana, where the locals gave him a "great ovation".

[35] Milligan died of natural causes at his son's home in Huntington County, Indiana, on December 21, 1899, thirty-three years after the U.S. Supreme Court ruling in the case that bore his name.

[3] Ex parte Milligan became well known as the leading U.S. Supreme Court case that found the president went beyond his legal powers to suppress dissenters during the American Civil War.