Despite a consensus stretching back hundreds of years that a “jury” consists of twelve people, in 1970 the Supreme Court held in Williams v. Florida that juries as small as six are constitutionally permissible under the Sixth Amendment. 

After being convicted by an eleven-person jury in the United States District Court for the District of Maryland, the petitioners in this case alleged that a jury of that size violated their Sixth Amendment jury trial right, which they argue ensures the right to a verdict by a jury of no fewer than twelve. They argued, among other things, that Williams is inconsistent with the 2020 case Ramos v. Louisiana, in which the Supreme Court overturned its own precedent and held that the Sixth Amendment requires that a jury verdict be unanimous in order to convict. That holding was premised on the notion that the meaning of the Sixth Amendment’s jury trial right is determined by looking at the meaning of the term at the time of the Amendment’s adoption. Applying that reasoning, the petitioners argue that because juries at the time of the Founding consisted of twelve members, the Sixth Amendment requires no less. 

The Fourth Circuit rejected this argument, and the petitioners subsequently filed a petition for a writ of certiorari in the U.S. Supreme Court. In September 2025, CAC filed an amicus brief in support of the petitioners’ certiorari petition, explaining why the Sixth Amendment requires that criminal juries consist of at least twelve people. 

Our brief makes three main points. 

First, our brief explains that at the Founding, juries were understood to consist of twelve people. This right had its foundation in English common law, which recognized the jury as critical to the preservation of liberty. At common law, an individual could only be convicted in a criminal trial by the unanimous consent of twelve of his neighbors and equals. As debates and commentary from the time of the Sixth Amendment’s adoption confirm, when the Framers included a right to a “jury” trial in the Constitution, they meant the right to a jury composed of at least twelve people. And the twelve-person requirement was repeatedly recognized by the Supreme Court, state supreme courts, and influential legal thinkers throughout the nineteenth and early twentieth centuries. 

Second, our brief explains that the Williams Court improperly dismissed the history of the Sixth Amendment in determining its meaning. Williams relied primarily on the drafting history of the Sixth Amendment to support its conclusion that the Framers did not mean to include the essential features of the jury from common law. But the Supreme Court explicitly rejected that reasoning in Ramos, noting that it would leave the right to a jury trial “devoid of meaning.” By ignoring the historical backdrop from which the right was derived and relying instead on its finding that six- and twelve-person juries are “functionally equivalent,” the Williams decision is plainly at odds with long-standing Supreme Court precedent recognizing that it is the original understanding of the Sixth Amendment that controls its meaning, not some abstract functionalist analysis. 

Third, even the functionalist analysis that Williams relied on leads to the conclusion that juries of fewer than twelve people undermine the right to a fair trial guaranteed by the Sixth Amendment. Williams assessed the effect of jury size along three main dimensions: the quality of jury deliberations, the ability of the jury to properly represent a cross-section of the community, and the reliability of jury verdicts. But the studies Williams relied on for its determination that six-person juries performed just as well along these metrics were not studies at all, but mere conclusory statements based on anecdote. Not only were these conclusions unsupported, they were also demonstrably wrong at the time based on well-known tenets of statistical theory. Finally, studies conducted since Williams consistently show as an empirical matter that juries smaller than twelve are worse in every regard Williams identified as being essential to the Sixth Amendment’s jury trial right.