Of wealthy Maryland birth, Davis was educated at Kenyon College and Yale University, before settling in Bloomington, Illinois, in the 1830s, where he practiced law. He served in the Illinois legislature and as a delegate to the state constitutional convention before becoming a state judge in 1848. Shortly after Lincoln won the presidency he appointed the determinedly independent Davis to the United States Supreme Court, where he served until 1877. Davis wrote the majority opinion in Ex parte Milligan, a significant judicial decision limiting the military's power to try civilians in its courts. After being nominated for president by the Labor Reform party in 1872 he pursued the Liberal Republican Party's nomination, but was defeated at the convention by Horace Greeley; despite this, he received one electoral vote in the 1872 presidential election.
Davis was a pivotal figure in Congress's establishment of the 1876 Electoral Commission charged with resolving the disputed Hayes v. Tilden presidential election; he was widely expected to serve as the deciding member of the Commission, but after the Democratic-controlled Illinois State Legislature sought to influence his vote by electing him to the U.S. Senate, Davis excused himself from the Commission and resigned from the Supreme Court to take the Senate appointment. A Republican was appointed in his place, handing the election to Rutherford B. Hayes.
On the Court, Davis became famous for writing one of the most profound decisions in Supreme Court history, Ex parte Milligan (1866). In that decision, the court set aside the death sentence imposed during the Civil War by a military commission upon a civilian, Lambdin P. Milligan. Milligan had been found guilty of inciting insurrection. The Supreme Court held that since the civil courts were operative, the trial of a civilian by a military tribunal was unconstitutional. The opinion denounced arbitrary military power, effectively becoming one of the bulwarks of held notions of American civil liberty.
In Hepburn v. Griswold (1870) he held with the minority of the Supreme Court, which ruled that the acts of Congress making government notes legal tender in payment of debts were unconstitutional.[1] He is the only justice of the Supreme Court with no recorded affiliation to any religious organization.[6][when?]
After refusing calls to become Chief Justice, Davis, a registered independent, was nominated for president by the Labor Reform Convention in February 1872 on a platform that declared, among other things, in favor of a national currency "based on the faith and resources of the nation", and interchangeable with 3.65% bonds of the government, and demanded the establishment of an eight-hour law throughout the country, and the payment of the national debt "without mortgaging the property of the people to enrich capitalists." In answer to the letter informing him of the nomination, Judge Davis said: "Be pleased to thank the convention for the unexpected honor which they have conferred upon me. The chief magistracy of the republic should neither be sought nor declined by any American citizen."[1]
He withdrew from the presidential contest when he failed to receive the Liberal Republican Party nomination, which went to editor Horace Greeley. Greeley died after the popular election and before the return of the electoral vote. One of Greeley's electoral votes went to Davis.
Hayes-Tilden Election Commission
In 1877, Davis narrowly avoided the opportunity to be the only person ever to single-handedly select the President of the United States. In the disputed Presidential election of 1876 between the Republican Rutherford Hayes and the Democrat Samuel Tilden, Congress created a special Electoral Commission to decide to whom to award a total of 20 electoral votes which were disputed from the states of Florida, Louisiana, South Carolina and Oregon. The Commission was to be composed of 15 members: five drawn from the U.S. House of Representatives, five from the U.S. Senate, and five from the U.S. Supreme Court. The majority party in each legislative chamber would get three seats on the Commission, and the minority party would get two. Both parties agreed to this arrangement because it was understood that the Commission would have seven Republicans, seven Democrats, and Davis, who was arguably the most trusted independent in the nation.
According to one historian, "No one, perhaps not even Davis himself, knew which presidential candidate he preferred."[7] Just as the Electoral Commission Bill was passing Congress, the legislature of Illinois elected Davis to the Senate. Democrats in the Illinois Legislature believed that they had purchased Davis's support by voting for him. However, they had made a miscalculation; instead of staying on the Supreme Court so that he could serve on the Commission, he promptly resigned as a Justice, in order to take his Senate seat. Because of this, Davis was unable to assume the spot, always intended for him, as one of the Supreme Court's members of the Commission. His replacement on the Commission was Republican Joseph Philo Bradley, resulting in an 8–7 majority for that party – which in turn awarded each of the 20 disputed electoral votes, and the Presidency, to Hayes by that outcome, 185 electoral votes to 184.
United States Senate
Davis served only a single term as U.S. Senator from Illinois (1877–1883), yet still played a meaningful role in U.S. history.
Upon the assassination of President James A. Garfield in 1881, Vice President Chester Arthur succeeded to the office of president. Per the terms of the Presidential Succession Act of 1792, which was still in effect, any subsequent vacancy of the office during the remaining 3½ years in Garfield's term would be filled by the President pro tempore of the Senate. As the Senate was evenly divided between the parties, this posed the risk of deadlock. To prevent this the independent Senator Davis was elected to preside over the Senate.[8] At the end of his term Davis did not seek re-election, instead retiring to his home in Bloomington.[1]