Appointment

On February 7, 1870, President Ulysses S. Grant nominated Bradley as an associate justice of the Supreme Court of the United States,^[4] to the seat created by the Judiciary Act of 1869. Several weeks later, on March 21, he was confirmed by the U.S. Senate by a 46–9 vote.^[4] Bradley took the judicial oath of office on March 23, 1870, and remained on the Court until January 22, 1892.^[5] Bradley was the president's second nominee for the position. The first, Ebenezer R. Hoar was rejected by the Senate.^[4]

Court jurisprudence

Bradley took a broad view of the national government's powers under the Commerce Clause but interpreted the Fourteenth Amendment somewhat narrowly, as did much of the rest of the court at the time. He authored the majority opinion in the Civil Rights Cases of 1883 but was among the four dissenters in the Slaughter-House Cases in 1873. His interpretation of the Fourteenth Amendment in both cases remained the basis for subsequent rulings through the modern era.

Bradley concurred with the court's decision in Bradwell v. Illinois, which held that the right to practice law was not constitutionally protected under the Privileges or Immunities Clause of the Fourteenth Amendment. Bradley disagreed with the majority opinion, apparently because it rested on the decision in the Slaughter-House Cases, but concurred in the judgment on grounds that the clause did not protect women in their choice of vocation. The concurrence is noted for Bradley's description of womanhood: "The harmony, not to say identity, of interest and views which belong, or should belong, to the family institution is repugnant to the idea of a woman adopting a distinct and independent career from that of her husband (...) The paramount destiny and mission of women are to fulfill the noble and benign offices of wife and mother. This is the law of the Creator."

It was due to Bradley's intervention that prisoners charged in the Colfax Massacre of 1873 were freed, after he happened to attend their trial and ruled that the federal law they were charged under was unconstitutional. This resulted in the federal government's bringing the case on appeal to the Supreme Court as United States v. Cruikshank (1875). The court's ruling on this case meant that the federal government would not intervene on paramilitary and group attacks on individuals. It essentially opened the door to heightened paramilitary activity in the South that forced Republicans from office, suppressed black voting, and opened the way for white Democratic takeover of state legislatures, and resulting Jim Crow laws and passage of disfranchising constitutions.

Bradley dissented in Chicago, Milwaukee & St. Paul Railway Co. v. Minnesota, which, though not racially motivated, was another due process case arising from the Fourteenth Amendment. In his dissent, Bradley argued that the majority had in siding with the railroad created a situation where the reasonableness of an act of a state legislature was a judicial question, subjugating the legislature to the will of the judiciary. Bradley's opinion in this case is echoed in modern arguments regarding judicial activism.

Bradley also wrote the opinion in Hans v. Louisiana, holding that a state could not be sued in a federal court by one of its own citizens. This is perhaps ironic in light of his dissent in the railroad case, since the Hans doctrine is entirely based on judicial activism and, as Bradley admitted in his opinion, not supported by the text of the Constitution.

As an individual Supreme Court Justice, Bradley decided In re Guiteau, a petition for habeas corpus filed on behalf of Charles Guiteau, the assassin of President James A. Garfield. Guiteau's lawyers argued that he had been improperly tried in the District of Columbia because, although Guiteau shot Garfield in Washington, D.C., Garfield died at his home in New Jersey. Bradley denied the petition in a lengthy opinion and Guiteau was executed.