Law360 (August 14, 2026, 11:46 PM EDT) -- Former judges, ex-prosecutors, criminal defense attorneys, civil rights groups, Catholic bishops, university professors and others are urging the U.S. Supreme Court to find that the Constitution requires 12-person juries to decide trials for serious crimes, taking aim at Florida's practice of seating six-person juries for most criminal trials.

Over a dozen amicus briefs were filed Thursday in support of Florida petitioner Hamed Kian, who was found guilty by a six-person jury on five felony counts of practicing chiropractic medicine with a suspended license and who contends his trial rights under the Sixth and 14th amendments were violated.

The Supreme Court agreed to take up the case in June, and in doing so revisit its 1970 decision in Williams v. Florida , in which a seven-member majority held that 12-member juries aren't an indispensable component of the Sixth Amendment right to trial by jury, as applied to states through the 14th Amendment.

Federal courts and the vast majority of U.S. states mandate that criminal trials for serious offenses must be decided by 12-person juries. However, in Florida, all noncapital offenses are tried before six-member juries. Five other states — Arizona, Connecticut, Indiana, Massachusetts and Utah — use juries of less than 12 people in some criminal cases.

Kian finds considerable support from a range of voices in the legal community, including the NAACP, former judges and prosecutors, the American Civil Liberties Union, the National Association of Criminal Defense Lawyers, legal scholars, public defenders, the CATO Institute and Human Rights for Kids.

Trial by jury has meant a trial by 12 for 600 years, the NACDL said in its brief, tracing the rule from "its common-law origins to early American practice through this court's precedents up until 1970."

The Williams court veered off course based on "since-debunked social science studies and its own views about the importance of jury size," according to the NACDL, but a half-century of studies have since shown that the traditional jury of 12 is "better able to process the evidence, arguments and instructions in a lengthy or complex trial" than juries of fewer members.

"The twelve-member jury's capacity for 'better testing of ideas and reactions' yields 'more accurate factual determinations,'" the NACDL said. "And improved accuracy shields the innocent from erroneous conviction — without making conviction of the guilty unduly difficult."

The U.S. Conference of Catholic Bishops backed up that argument in a history-dense brief of its own, which chronicles what it calls "the ancient tradition" that underlies the requirement of a 12-member jury. The Williams court erroneously concluded that the 12-member mandate was an "'accidental feature of the jury,'" they say.

"By at least the fourteenth century, 'it had already become an 'ancient prerogative' to have twelve laymen stand between [an Englishman] and the vengeance of the king in a criminal prosecution," the bishops argued.

Kian seemingly has one vote already in the bag, in light of multiple dissents from denials of certiorari by Justice Neil Gorsuch.

"Florida does what the constitution forbids because of us," Justice Gorsuch said in Cunningham v. Florida , in reference to the "revolutionary decision" in Williams allowing six-member juries.

In another brief, a coalition of former state and federal judges and current and former prosecutors and police leaders argue that the administration of criminal justice hinges on the public's trust and respect of the judicial process, which federal courts and most states have long recognized includes a guarantee of 12-person juries for serious criminal cases.

"When twelve members of the community hear the evidence, deliberate, and unanimously pronounce judgment, the verdict carries an authority no prosecutor or law enforcement officer could marshal alone," those amici say. "That is because the public is more likely to accept the outcome when a representative jury drawn from the community decides it."

For its part, Florida tracks the state's tradition of six-member juries for non-capital crimes to 1877 — the end of post-Civil War reconstruction — when the Florida Supreme Court ruled that the practice neither destroys nor infringes the right of a trial by jury.

"The petitioner makes no serious attempt to show that overruling Williams is warranted under traditional principles of stare decisis, and it is not," the office of Florida Attorney General James Uthmeier said in an April 20 opposition brief.

Florida contends that it will be a logistical nightmare if the Supreme Court overturns Williams, considering the roughly 5,000 criminal convictions that are on appeal in the state, which could be forced to allow some convicted criminals to walk if thousands of retrials must be conducted.

Representatives for Uthmeier's office did not immediately respond to a request for comment late Friday.

A band of law professors from Northwestern Pritzker Law, the University of Michigan Law School, Cornell Law School and elsewhere argued that the Williams court ignored "widely understood aspects of the statistics of sampling" in deciding there was no discernable difference between a 12-person panel and a six-member body when it comes to the critical functions of juries.

The law professors say that replacing larger juries with smaller ones leads to more juries that have no members of minority groups from the population, "and applies to all kinds of minorities, whether religious, racial, occupational or viewpoint."

"Today, it is clear that both statistics and empirical research show that six-person juries are inferior to twelve-person juries," the professors' brief says. "The traditional jury of twelve has been sliced in half with no theory of any kind to support the slicing."

According to Kian, even if the Supreme Court was to revisit the Sixth Amendment, the logic behind Williams doesn't hold up.

"Twelve-member juries deliberate longer, recall evidence better, and rely less on irrelevant factors during deliberation," Kian argued in his petition.

Juries were limited to smaller groups in certain states like Florida during the Jim Crow era, the cert petition said.

Kian noted that Justice Gorsuch deemed this to be a part of a "deliberate and systematic effort to suppress minority voices in public affairs," he said in a dissent to denial of certiorari in Khorrami v. Arizona , a 2022 case asking the court to consider whether an eight-person jury was permissible in noncapital criminal trials.

According to his cert petition, Kian was charged with five counts of practicing chiropractic medicine with a suspended license and was convicted by the six-person jury and sentenced to more than one year in prison. Florida's Fourth District Court of Appeal affirmed his conviction.

Akhil Reed Amar of Yale Law School is represented by Christopher Duggan of Smith Duggan Cornell & Gollub LLP.

Maricopa County Indigent Representation Offices is represented by Mikel Steinfeld, Lina Garcia, Shannon Burns, Michael Jones, Steve Koestner and Rosemarie Pena-Lynch of the Office of the Maricopa County Public Defender.

The Constitutional Accountability Center is represented in-house by Elizabeth Wydra, Brianne Gorod and Joshua Belcher-Cohen.

The NACDL is represented by Jonathan Hacker, Arjun Ogale, Matt Aidan Getz, Kahn Scolnick, Patrick Fuster, Paige Petrashko and Tate Rosenblatt of Gibson Dunn & Crutcher LLP.

Human Rights For Kids is represented in-house by James Dold, Teresa Kominos and Suzanne La Pierre.

The Juror Project is represented by Jo-Ann Sagar, Eric Roytman-Cash and Ashwin Fujii of Hogan Lovells Cadwalader.

Steven Calabresi et al. are represented by Stephen Senn and Nicholas Sellars of Peterson & Myers PA and Sarah Lahlou-Amine.

Wanling Su is represented by Eamon Joyce, Jacob Steinberg-Otter, Kimberly Quick and Bianca Mona of Sidley Austin LLP.

The Innocence Project et al. are represented in-house by M. Chris Fabricant, Matthew Wasserman, Seth Miller and Craig Trocino and by Adam Gershenson, Brian Liegel, Sarah Sternlieb, Dylan Brown and McKayla Robinson of Weil Gotshal & Manges LLP.

The ACLU et al. are represented in-house by Cecillia Wang and by Devi Rao of MacArthur Justice.

Fair and Just Prosecution et al. are represented by Daniel Woofter and Kevin Russell of Russell & Woofter LLC.

The Utah Association of Criminal Defense Lawyers is represented in-house by Dallas Young.

The NAACP is represented in-house by Brittany Carter, Samuel Spital, Janai Nelson, Daniel Harawa and Christopher Kemmitt.

The Florida Association of Criminal Defense Lawyers et al. are represented in-house by Cliff Wilson Jr., Jackie Perczek of Black Srebnick, and Daniel Tibbitt.

The U.S. Conference of Catholic Bishops is represented in-house by William Quinn and by Noel Francisco, Anthony Dick, John Brinkerhoff Jr. and Amanda Rice of Jones Day.

Florida is represented by Celia Terenzio and Joseph Mollica of the Office of the Attorney General for the State of Florida.

Kian is represented by Seth Waxman, Alex Miller, Adela Lilollari and Thomas Sprankling of WilmerHale and Daniel Eisinger, Paul Petillo and Benjamin Eisenberg of the Office of the Public Defender for Florida's Fifteenth Judicial Circuit.

The case is Hamed Kian v. Florida, case number 25-6623, in the Supreme Court of the United States.

--Additional reporting by Elizabeth Daley. Editing by Jay Jackson Jr.

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