The Puzzle of Unanimity: Consensus on the United States Supreme Court

The Puzzle of Unanimity: Consensus on the United States Supreme Court

The Puzzle of Unanimity: Consensus on the United States Supreme Court

The Puzzle of Unanimity: Consensus on the United States Supreme Court


The U.S. Supreme Court typically rules on cases that present complex legal questions. Given the challenging nature of its cases and the popular view that the Court is divided along ideological lines, it's commonly assumed that the Court routinely hands down equally-divided decisions. Yet the justices actually issue unanimous decisions in approximately one third of the cases they decide.

Drawing on data from the U.S. Supreme Court database, internal court documents, and the justices' private papers, The Puzzle of Unanimity provides the first comprehensive account of how the Court reaches consensus. Pamela Corley, Amy Steigerwalt, and Artemus Ward propose and empirically test a theory of consensus; they find consensus is a function of multiple, concurrently-operating forces that cannot be fully accounted for by ideological attitudes. In this thorough investigation, the authors conclude that consensus is a function of the level of legal certainty and its ability to constrain justices' ideological preferences.


On March 4, 1998, the United States Supreme Court issued a unanimous ruling in the same-sex harassment case Oncale v. Sundowner Offshore Services (1998). At issue was whether Title VII’s protection against workplace discrimination “because of … sex” applies to harassment between members of the same sex. Joseph Oncale was employed as a roustabout on an oil platform in the Gulf of Mexico and was subjected to humiliating sex-related actions by some of his co-workers in front of the rest of the crew. He complained to supervisory personnel, but received no relief and eventually resigned. Oncale filed suit in federal district court, alleging that he was discriminated against because of his sex. The district court, relying on a Fifth Circuit Court of Appeals decision in Garcia v. Elf Atochem North America (1994), held that he had no cause of action because same-sex sexual harassment claims are never cognizable under Title VII. The Fifth Circuit affirmed, and the Supreme Court granted certiorari.

Although lower courts “[had] taken a bewildering variety of stances” on whether Title VII prohibits same-sex sexual harassment cases, the Court unanimously held in Oncale that “nothing in Title VII necessarily bars a claim of discrimination ‘because of … sex’ merely because the plaintiff and the defendant … are of the same sex” (Oncale, 79). According to the majority opinion written by Justice Antonin Scalia (ibid., 79), “[w]e see no justification in the statutory language or our precedents for a categorical rule excluding same-sex harassment claims from coverage of Title VII.” Thus, Oncale definitively and unanimously set the precedent for analyzing samesex harassment claims.

Why were the justices able to reach complete agreement in Oncale? More broadly, how do we explain decisions where conservative justices agree with liberal justices on potentially contentious issues? Media accounts routinely paint a portrait of a deeply ideologically divided Court. For example, a recent article argued that patterns of law clerk hiring “amplify the ideological rifts on a polarized court” (Liptak 2010). Another account, discussing oral . . .

Search by... Author
Show... All Results Primary Sources Peer-reviewed


An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.