This article examines the Supreme Court's 1977 decision in Illinois Brick Co. v. Illinois, 431 U.S. 720 (1977) through the now public papers of Justices Blackmun, Brennan, Marshall and Powell. These papers illuminate all phases of consideration of the case, from the treatment of the petition for a writ of certiorari, to the evaluation of the merits of the case by the clerks and the Justices, and the evolution of the Court's majority and dissenting opinions. Perhaps the most striking discovery is that the initial conference vote in Illinois Brick was to affirm, upholding the right of indirect purchasers to sue. Within a week's time, however, five Justices changed their votes. Seemingly influenced by the leadership and arguments of Justice Byron White and others, the Court's initial 6-3 vote to affirm was transformed into a 6-3 vote to reverse. Although the papers of the Justices vary greatly in detail, they do suggest that several factors were of particular importance in reaching the Court's result. Clearly, a major change in the make-up of the Court and a change of judicial attitude toward antitrust and business was a significant factor. The import of that change was obscured to some degree owing to the common leadership of Justice White in drafting the majority decisions in both Hanover Shoe and Illinois Brick. Nevertheless, philosophically the two cases are difficult to reconcile, and it seems highly unlikely that the full Hanover Shoe Court would have decided Illinois Brick the same way. Leadership within and without the Court also influenced the outcome in Illinois Brick, with Justice White and a noted commentator playing important roles in shaping the arguments that ultimately prevailed. Other factors were also in evidence, such as the role of the clerks, of the Solicitor General, who appeared as an amicus, and of the broader readiness of the Court to strike out in a new direction in antitrust. The article concludes with some observations about what the Justices' papers on Illinois Brick reveal about the process of change at the Supreme Court relative to other decisions of the time. It also looks at judicial developments subsequent to Illinois Brick, which suggest that the Court's continuing support for the economic reasoning of the case eroded over time. Finally, I pose a question that bears upon our understanding of Illinois Brick, but more broadly on the institutional role that the Supreme Court plays in establishing national competition policy: what are the sources of the Court's economic ideas, and what institutional filters exist to ensure that the Court embraces sound economic reasoning when it formulates that policy?
