While the Court was extremely divided in their rulings, they unanimously concurred that a criminal conviction based on a jury of less than six members is unconstitutional.

In his opinion, Justice Harry Blackmun held that a criminal trial to a jury of less than six members substantially threatened the Sixth and Fourteenth Amendments. In response to the lower court’s reliance on Williams v. Florida (1970), Blackmun noted that the Court’s holding that case “expressly reserved ruling on the issue whether a number smaller than six passed constitutional scrutiny.” He explained that while the Court was not prepared then to speculate on what, if any, number of jurors the Constitution required, they were now forced to. Writing for a divided Court/joined by Justice John Paul Stevens, Blackmun held that

Blackmun pointed out that juries with memberships of less than five face several issues avoided by a larger group. He argued that the smaller the group, the fewer individual members are able to overcome their personal biases, the fewer members will remember specific pieces of evidence, and members are less likely to provide critical contributions to solving the problem. In addition, he noted studies that found that the risk of convicting an innocent person rose as jury size decreased and expressed concern that the shrinking size of juries would proportionately exclude minority participation. In larger groups, however, Blackmun argued that members are more motivated to find an accurate solution and be self-critical of their work. Explaining his concerns, he wrote, “[w]e readily admit that we do not pretend to discern a clear line between six members and five. But the assembled data raise substantial doubt about the reliability and appropriate representation of panels smaller than six. Because of the fundamental importance of the jury trial to the American system of criminal justice, any further reduction that promotes inaccurate and possibly biased decisionmaking, that causes untoward differences in verdicts, and that prevents juries from truly representing their communities, attains constitutional significance.”

Responding to Georgia’s argument that a five-member jury was acceptable so long as the defendant was facing a misdemeanor charge, Blackmun cited the Court’s ruling in Baldwin v. New York (1970), which held that the right to a jury applied in both felony and misdemeanor cases. He explained, “[w]e cannot conclude that there is less need for the imposition and the direction of the sense of the community in this case than when the State has chosen to label an offense a felony. The need for an effective jury here must be judged by the same standards announced and applied in Williams v. Florida [1970].” Blackmun concluded that “the purpose and functioning of the jury in a criminal trial is seriously impaired, and to a constitutional degree, by a reduction in size to below six members.”