Edwin McMasters Stanton (December 19, 1814 – December 24, 1869), was an American lawyer, politician, United States Attorney General in 1860-61 and Secretary of War through most of the American Civil War and Reconstruction era. Less notable is the debate of whether Stanton served a short term as an Associate Justice on the United States Supreme Court.

Stanton was born in Steubenville, Ohio, the eldest of the four children of David and Lucy (Norman) Stanton. His father was a physician of Quaker stock. Stanton began his political life as a lawyer in Ohio and an antislavery Democrat. After leaving from Kenyon College in 1833 to get a job to support his family, he was admitted to the Ohio bar in 1836. Stanton built a house in the small town of Cadiz, Ohio, and practiced law there until 1847, when he moved to Pittsburgh, Pennsylvania.

In 1856, Stanton moved to Washington, D.C., where he had a large practice before the Supreme Court. In 1859, Stanton was the defense attorney in the sensational trial of Daniel E. Sickles, a politician and later a Union general, who was tried on a charge of murdering his wife's lover, Philip Barton Key, II (son of Francis Scott Key), but was acquitted after Stanton invoked the first use of the insanity defense in U.S. history.

In 1860 he was appointed as Attorney General by President James Buchanan. He strongly opposed secession, and is credited by historians for changing Buchanan's position away from tolerating secession to denouncing it as unconstitutional and illegal.

Stanton was politically opposed to Republican Abraham Lincoln in 1860. After Lincoln was elected president, Stanton agreed to work as a legal adviser to the inefficient Secretary of War, Simon Cameron, whom he replaced on January 15, 1862. He accepted the position only to "help save the country." He was very effective in administering the huge War Department, but devoted considerable amounts of his energy to the persecution of Union officers whom he suspected of having traitorous sympathies for the South. On August 8, 1862 Stanton issued an order to "arrest and imprison any person or persons who may be engaged, by act, speech or writing, in discouraging volunteer enlistments, or in any way giving aid and comfort to the enemy, or in any other disloyal practice against the United States."

The president recognized Stanton's ability, but whenever necessary Lincoln managed to "plow around him." Stanton once tried to fire the Chief of the War Department Telegraph Office, Thomas Eckert. Lincoln prevented this by defending Eckert and told Stanton he was doing a good job. This led to Eckert keeping his job. Yet, when pressure was exerted to remove the unpopular secretary from office, Lincoln replied, "If you will find another secretary of war like him, I will gladly appoint him." Stanton became a Republican and apparently changed his opinion of Lincoln. At Lincoln's death Stanton remarked, "Now he belongs to the ages," and lamented, "There lies the most perfect ruler of men the world has ever seen." He vigorously pursued the apprehension and prosecution of the conspirators involved in Lincoln's assassination. These proceedings were not handled by the civil courts, but by a military tribunal, and therefore under Stanton's tutelage. Stanton has subsequently been accused of witness tampering, most notably of Louis J. Weichmann, and of other activities that skewed the outcome of the trials.

Stanton continued to hold the position of secretary of war under President Andrew Johnson until 1868. His relations with the president were not good, and Johnson attempted to remove Stanton from the Cabinet and replace him with General Lorenzo Thomas. Stanton, however, barricaded himself in his office, and the radicals in Congress, claiming that Johnson's actions violated the Tenure of Office Act, initiated impeachment proceedings against him. Johnson however escaped conviction by a single vote.

After this, Stanton resigned and returned to the practice of law. The next year he was appointed by President Grant to the Supreme Court, but he died four days after he was confirmed by the Senate, and taking the oath of office on his deathbed, set the record for shortest tenure on the Court. He died in Washington, DC, and is buried there in Oak Hill Cemetery.

This point is disputed by the Supreme Court web site itself in its official Justices PDFwhich does not list Stanton as a Justice of the Supreme Court, but notes that:

"The acceptance of the appointment and commission by the appointee, as evidenced by the taking of the prescribed oaths, is here implied; otherwise the individual is not carried on this list of the Members of the Court. Examples: ..... Edwin M. Stanton who died before he could take the necessary steps toward becoming a Member of the Court."

One Dollar Treasury Notes, also called Coin Notes, of the Series' 1890 and 1891 feature portraits of Stanton on the obverse. Stanton also appears on the fourth issue of Fractional Currency, in the amount of 50 cents. Stanton Park, four blocks from the U.S. Capitol in Washington, D.C., is named for him, as is Stanton College Preparatory School in Jacksonville, Florida. A steam engine, built in 1862, was named the "E. M. Stanton" in honor of the new Secretary of War.

*In the 1930s, a book written by Otto Eisenschiml accused Stanton of arranging the assassination of Lincoln. Although these charges remain largely unsubstantiated, Eisenschim's book inspired considerable debate and the 1977 book and movie, The Lincoln Conspiracy.

*In 1930, Stanton was portrayed by Oscar Apfel in the movie Abraham Lincoln.

*In 1972, Stanton appears in Philip K Dick's We Can Build You in the form of a self-aware, cybernetic automaton.

*In 1980, Stanton was portrayed by Richard A. Dysart in the TV movie The Ordeal of Dr. Mudd.

*Stanton appears prominently in the alternate history Civil War trilogy by Newt Gingrich and William R. Forstchen.

*Stanton Davis Kirkham was named after Stanton by his father, Murray S. Davis, one-time confidential military aide to Stanton during his period as Secretary of War. (Source: "Olden Times in Colorado" by Carlyle Channing Davis.)

*Goodwin, Doris Kearns. Team of Rivals: The Political Genius of Abraham Lincoln (2005) on Lincoln's cabinet. *William Hanchett The Lincoln Murder Conspiracies (1983); demolishes the allegation that Stanton was the center of the plot to assassinate Lincoln *Hendrick, Burton J. Lincoln's War Cabinet (1946) *Harold M. Hyman, "Johnson, Stanton, and Grant: A Reconsideration of the Army's Role in the Events Leading to Impeachment," American Historical Review 66 (Oct. 1960): 85-96, online in JSTOR *Meneely, A. Howard, "Stanton, Edwin McMasters," in Dictionary of American Biography, Volume 9 (1935) *Pratt, Fletcher. Stanton: Lincoln's Secretary of War (1953). *Simpson, Brooks D. Let Us Have Peace: Ulysses S. Grant and the Politics of War and Reconstruction, 1861-1868 (1991) *Skelton, William B. . "Stanton, Edwin McMasters"; American National Biography Online 2000. *Thomas, Benjamin P., and Hyman, Harold M. Stanton: The Life and Times of Lincoln's Secretary of War (1962), the standard scholarly biography. *Stanton, Edwin (Edited by: Ben Ames Williams Jr.) Mr. Secretary (1940), partial autobiography.

*Spartacus Educational: Edwin M. Stanton *Biography from "Impeach Andrew Johnson" *Mr. Lincoln's White House: Edwin M. Stanton Biography *Mr. Lincoln and Friends: Edwin M. Stanton Biography *Stanton biography in Columbia Electronic Encyclopedia, 6th ed. *Pictures of US Treasury Notes featuring Edwin Stanton, provided by the Federal Reserve Bank of San Francisco. *Pictures of Fractional Currency featuring Edwin Stanton, provided by the Federal Reserve Bank of San Francisco.