Amicus Curiae Brief — Hamed Kian, Petitioner v. Florida

Supreme Court briefAug 13, 2026

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No. 25-6623

In The

Supreme Court of the United States

HAMED KIAN,

Petitioner,

STATE OF FLORIDA,

Respondent.

On Writ of Certiorari to the

Fourth District Court of Appeal of Florida

BRIEF OF CONSTITUTIONAL

ACCOUNTABILITY CENTER

AS AMICUS CURIAE

IN SUPPORT OF PETITIONER

ELIZABETH B. WYDRA

BRIANNE J. GOROD*

JOSHUA D. BLECHER-COHEN

CONSTITUTIONAL

ACCOUNTABILITY CENTER

1730 Rhode Island Ave. NW

Suite 1200

Washington, D.C. 20036

(202) 296-6889

brianne@theusconstitution.org

Counsel for Amicus Curiae

August 13, 2026

* Counsel of Record

TABLE OF CONTENTS

Page

TABLE OF AUTHORITIES ..................................

INTEREST OF AMICUS CURIAE ......................

INTRODUCTION AND SUMMARY OF

ARGUMENT.......................................................

ARGUMENT ..........................................................

At the Founding, Juries Were Composed

of Twelve People .........................................

II.

The Williams Court Improperly

Dismissed the Sixth Amendment’s

History in Determining Its Meaning .........

III. Empirical Research Shows that Juries of

Fewer than Twelve People Undermine

the Right to a Fair Trial Guaranteed by

the Sixth Amendment ................................

A. Deliberation Quality ........................

B. Community Representativeness .....

C. Verdict Quality .................................

CONCLUSION ......................................................

TABLE OF AUTHORITIES

Page(s)

Cases

Apodaca v. Oregon,

406 U.S. 404 (1972).....................................

Apprendi v. New Jersey,

530 U.S. 466 (2000)............................ 12, 13, 16

Baldwin v. New York,

399 U.S. 66 (1970) .................................... 10, 15

Ballew v. Georgia,

435 U.S. 223 (1978)....................... 5, 19, 20, 24

Blakely v. Washington,

542 U.S. 296 (2004).................................. 12, 16

Brown v. Louisiana,

447 U.S. 323 (1980).....................................

Cancemi v. People,

18 N.Y. 128 (1858) ......................................

Crawford v. Washington,

541 U.S. 36 (2004) .......................................

Foote v. Lawrence,

1 Stew. 483 (Ala. 1828) ...............................

Giles v. California,

554 U.S. 353 (2008).....................................

Khorrami v. Arizona,

143 S. Ct. 22 (2022).................................... 6, 14

Maxwell v. Dow,

176 U.S. 581 (1900).....................................

iii

TABLE OF AUTHORITIES – cont’d

Page(s)

Op. of the Justices of the Supreme Jud. Ct.,

41 N.H. 550 (1860) ......................................

Parsons v. Bedford,

28 U.S. (3 Pet.) 433 (1830) ..........................

Patton v. United States,

281 U.S. 276 (1930).....................................

Ramos v. Louisiana,

590 U.S. 83 (2020) ....................... 2-5, 10, 13-16

Rassmussen v. United States,

197 U.S. 516 (1905)................................. 11, 12

Smith v. Texas,

311 U.S. 128 (1940).....................................

State v. Everett,

14 Minn. 439 (1869) ....................................

Thompson v. Utah,

170 U.S. 343 (1898)............................. 4, 10, 13

United States v. Booker,

543 U.S. 220 (2005).....................................

Williams v. Florida,

399 U.S. 78 (1970) ............... 4, 5, 10, 12, 14, 15,

17, 18, 20, 23

Constitutional Provisions

Fundamental Constitutions of Carolina, 1669,

reprinted in 1 Bernard Schwartz, The Bill of

Rights: A Documentary History (1971) ......

TABLE OF AUTHORITIES – cont’d

Page(s)

U.S. Const. amend. V .....................................

U.S. Const. amend. VI ...................................

U.S. Const. amend. VII ..................................

Books, Articles, and Other Authorities

Akhil Reed Amar, The Bill of Rights: Creation

and Reconstruction (1998) .......................... 1, 7

Richard S. Arnold, Trial by Jury: The

Constitutional Right to a Jury of Twelve in

Civil Trials, 22 Hofstra L. Rev. 1 (1993) ... 7, 8

3 Matthew Bacon, A New Abridgement of the

Law (3d ed. 1768) ........................................

Larry T. Bates, Trial by Jury After Williams v.

Florida, 10 Hamline L. Rev. 53 (1987) ...... 7, 9

3 William Blackstone, Commentaries on the

Laws of England (1768).......................... 2, 7, 8

4 William Blackstone, Commentaries on the

Laws of England (1769).............. 1, 3, 8, 12, 13

3 The Debates in the Several State Conventions

on the Adoption of the Federal Constitution

(Jonathan Elliot ed., 1836) .........................

Shari Seidman Diamond et al., Achieving

Diversity on the Jury: Jury Size and the

Peremptory Challenge,

6 J. Empirical Legal Stud. 425

(2009) .................................................... 6, 21, 22

TABLE OF AUTHORITIES – cont’d

Page(s)

Thomas Ward Frampton, The Jim Crow Jury,

71 Vand. L. Rev. 1593 (2018) ..................... 22

Sir Matthew Hale, The History of the Common

Law of England (1713) ...............................

Patrick E. Higginbotham, Lee H. Rosenthal &

Steven S. Gensler, Better by the Dozen:

Bringing Back the Twelve-Person Civil Jury,

104 Judicature 46 (2020) ........................... 5, 17

Irwin A. Horowitz & Kenneth S. Bordens, The

Effects of Jury Size, Evidence Complexity, and

Note Taking on Jury Process and Performance

in a Civil Trial,

87 J. Applied Psych. 121 (2002) ................. 19

Harry Kalven, Jr. & Hans Zeisel, The American

Jury (1966) .................................................. 18

Norbert L. Kerr & Robert J. MacCoun, The

Effects of Jury Size and Polling Method on the

Process and Product of Jury Deliberation,

48 J. Pers. & Soc. Psych. 349 (1985) .......... 24

Richard O. Lempert, Uncovering

“Nondiscernible” Differences: Empirical

Research and the Jury-Size Cases,

73 Mich. L. Rev. 643 (1975) ........................

Letter from Hon. William Pierce to St. George

Tucker (Sept. 28, 1787), reprinted in 3 The

Documentary History of the Ratification of the

Constitution: Ratification of the Constitution

by the States (Merrill Jensen ed., 1978) ....

TABLE OF AUTHORITIES – cont’d

Page(s)

Robert H. Miller, Six of One Is Not a Dozen of

the Other: A Re-Examination of Williams v.

Florida and the Size of State Criminal Juries,

146 U. Pa. L. Rev. 621 (1998) ................. 3, 7, 9

Stuart S. Nagel & Marian Neef, Deductive

Modeling to Determine an Optimum Jury Size

and Fraction Required to Convict,

1975 Wash. U. L.Q. 933 ........................... 6, 24

Michael J. Saks & Mollie Weighner Marti, A

Meta-Analysis of the Effects of Jury Size,

21 L. & Hum. Behav. 451 (1997)............. 19-21

Alisa Smith & Michael J. Saks, The Case for

Overturning Williams v. Florida and the SixPerson Jury: History, Law, and Empirical

Evidence, 60 Fla. L. Rev. 441 (2008) ... 6, 18-23

Ivan D. Steiner, Group Process and Productivity

(1972) ........................................................... 19

2 Joseph Story, Commentaries on the

Constitution of the United States

(4th ed. 1873) ..............................................

2 Joseph Story, Commentaries on the

Constitution of the United States

(5th ed. 1891) ..............................................

Wanling Su & Rahul Goravara, What Is a Jury?,

103 N.C. L. Rev. 969 (2025)..................... 9, 18

James Bradley Thayer, A Preliminary Treatise

on Evidence at the Common Law (1898)... 3, 13

vii

TABLE OF AUTHORITIES – cont’d

Page(s)

Angelo Valenti & Leslie Downing, Six Versus

Twelve Member Juries: An Experimental Test

of the Supreme Court Assumption of

Functional Equivalence,

1 Pers. & Soc. Psych. Bull. 273 (1974) ....... 19

Angelo C. Valenti & Leslie L. Downing,

Differential Effects of Jury Size on Verdicts

Following Deliberation as a Function of the

Apparent Guilt of a Defendant,

32 J. Pers. & Soc. Psych. 655 (1975) .......... 24

David F. Walbert, The Effect of Jury Size on the

Probability of Conviction: An Evaluation of

Williams v. Florida,

22 Case W. Rsrv. L. Rev. 529 (1971) .......... 23

2 James Wilson, Works of the Honourable James

Wilson (1804) ........................................... 3, 10

Hans Zeisel, . . . And Then There Were None: The

Diminution of the Federal Jury,

38 U. Chi. L. Rev. 710 (1971) .. 5, 17, 18, 20, 21

INTEREST OF AMICUS CURIAE1

Constitutional Accountability Center (CAC) is a

think tank and public interest law firm dedicated to

fulfilling the progressive promise of the

Constitution’s text and history. CAC works in our

courts, through our government, and with legal

scholars to improve understanding of the

Constitution and preserve the rights and freedoms

it guarantees. CAC has a strong interest in ensuring

that the Constitution applies as robustly as its text

and history require and accordingly has an interest

in this case.

INTRODUCTION AND

SUMMARY OF ARGUMENT

The centrality of the jury to the Framers cannot

be overstated. “[A] paradigmatic image underlying

the original Bill of Rights,” the “jury summed up—

indeed embodied—the ideals of populism,

federalism, and civic virtue that were the essence of

the original Bill of Rights.” Akhil Reed Amar, The

Bill of Rights: Creation and Reconstruction 96-97

(1998).

The Founding generation’s focus on the jury as a

central feature of a system of ordered liberty was

strongly rooted in English common law. Blackstone,

for example, called the jury a “sacred bulwark” of

liberty. 4 William Blackstone, Commentaries on the

Laws of England 344 (1769). In his words, “the most

1 No counsel for a party authored this brief in whole or in

part, and no counsel or party made a monetary contribution

intended to fund its preparation or submission. No person

other than amicus or its counsel made a monetary contribution

to its preparation or submission.

transcendent privilege which any subject can enjoy,

or wish for, [is] that he cannot be affected either in

his property, his liberty, or his person, but by the

unanimous consent of twelve of his neighbours and

equals.” 3 William Blackstone, Commentaries on the

Laws of England 379 (1768).

Drawing on that history, this Court has held that

the Sixth Amendment, together with the Fourteenth

Amendment, guarantees criminal defendants in

state and federal court the right to a unanimous jury

verdict. See Ramos v. Louisiana, 590 U.S. 83, 93

(2020). Looking to “the common law, state practices

in the founding era, [and] opinions and treatises

written soon afterward,” Ramos concluded that

when the Sixth Amendment was adopted, “trial by

an impartial jury” necessarily meant that a “jury

must reach a unanimous verdict in order to convict.”

Id. at 90.

In so holding, this Court overruled an earlier

decision, Apodaca v. Oregon, that permitted states

to convict criminal defendants with nonunanimous

jury verdicts. See id. at 105-09 (discussing Apodaca

v. Oregon, 406 U.S. 404 (1972)). Apodaca was

premised on the view that the unanimity

requirement did not serve “an important function in

contemporary society.” Id. at 94 (quotation marks

omitted). In abrogating that decision, this Court

took the Apodaca plurality to task for “subject[ing]

the ancient guarantee of a unanimous jury verdict to

its own functionalist assessment”—an assessment

that was “gravely mistaken” even on its own terms.

Id. at 100, 106.

The same history and reasoning that led this

Court to overrule Apodaca and hold that the Sixth

Amendment requires jury unanimity also compel

the conclusion that the Sixth Amendment requires

juries to consist of at least twelve people. When the

Framers drafted the Constitution, “the twelveperson unanimous criminal jury was an institution

with a nearly four-hundred-year-old tradition in

England.” Robert H. Miller, Six of One Is Not a

Dozen of the Other: A Re-Examination of Williams v.

Florida and the Size of State Criminal Juries, 146 U.

Pa. L. Rev. 621, 643 (1998). Indeed, as the states

were ratifying the Sixth Amendment, Justice James

Wilson declared that “[t]o the conviction of a crime,

the undoubting and the unanimous sentiment of the

twelve jurors is of indispensable necessity.” 2 James

Wilson, Works of the Honourable James Wilson 350

(1804) (recording Wilson’s 1790s law lectures). The

jury right the Framers enshrined in the Constitution

was thus the right to a jury composed of twelve

people.

Significantly, many of the same sources this

Court relied on for its holding in Ramos also

instruct—often in the very same passage—that

juries must consist of at least twelve people. For

example, one source stated that “the truth of every

accusation . . . should . . . be confirmed by the

unanimous suffrage of twelve of his equals and

neighbours.” Ramos, 590 U.S. at 90 (alterations in

original) (emphasis added) (quoting 4 Blackstone,

Commentaries 343). Another provided that “a

‘verdict, taken from eleven, was no verdict’ at all.”

Id. (quoting James Bradley Thayer, A Preliminary

Treatise on Evidence at the Common Law 88-89 n.4

(1898)). And a third instructed that “a defendant

enjoys a ‘constitutional right to demand that his

liberty should not be taken from him except by the

joint action of the court and the unanimous verdict

of a jury of twelve persons.’” Id. at 92 (emphasis

added) (quoting Thompson v. Utah, 170 U.S. 343,

351 (1898)).

Despite the clear historical evidence that juries

consisted of at least twelve people at the Framing,

Hamed Kian was found guilty of five criminal

charges by a jury with only six members. See Pet.

App. 3a, 5a. That result was possible because this

Court in Williams v. Florida permitted juries of as

few as six people to convict criminal defendants. See

399 U.S. 78, 103 (1970).

But the same problems that doomed Apodaca

haunt Williams in equal measure. Decided two

years before Apodaca, Williams dismissed the long

history confirming that the size of a jury has been

fixed at twelve for over six hundred years as a

“historical accident,” id. at 89, and rejected what it

termed the “easy assumption” that “if a given

feature existed in a jury at common law in 1789,

then it was necessarily preserved in the

Constitution,” id. at 92. Williams then conducted a

functionalist analysis of the jury right, concluding

that there was “little reason to think” that the goals

of the Sixth Amendment “are in any meaningful

sense less likely to be achieved when the jury

numbers six.” Id. at 100.

Williams, like Apodaca soon after it, wrongly

rejected the common-law history underlying the

Sixth Amendment. As this Court’s more recent

precedents make clear, it is improper to conduct a

“functionalist analysis” of the jury right that

“overlooks the fact that, at the time of the Sixth

Amendment’s adoption, the right to trial by jury”

meant a jury of twelve people. Ramos, 590 U.S. at

100, 106.

Further, just like the empirical evidence Apodaca

invoked, the evidence on which Williams relied

failed to reckon with—and drastically understated—

the deficiencies of juries with fewer than twelve

members. Williams cited the “few experiments” it

could find on the effect of jury size on verdict quality,

Williams, 399 U.S. at 101, but these so-called

experiments “were not empirical studies,” Patrick E.

Higginbotham, Lee H. Rosenthal & Steven S.

Gensler, Better by the Dozen: Bringing Back the

Twelve-Person Civil Jury, 104 Judicature 46, 52

(2020). Instead, they were merely “conclusory

statements . . . supported at best by limited

experience and anecdote.” Id. And even those

conclusory statements were contradicted by

“elementary statistical theory” that was “well

established” at the time. Hans Zeisel, . . . And Then

There Were None: The Diminution of the Federal

Jury, 38 U. Chi. L. Rev. 710, 715 n.32 (1971).

According to Williams, six-person juries

deliberate just as well as twelve-person juries, are

just as capable of representing a fair cross-section of

the community, and produce verdicts of identical

quality. See Williams, 399 U.S. at 100-02. But more

recent academic research sheds new light on the

relationship between jury size and the quality of

their

deliberations,

representativeness,

and

decisions. Cf. Ballew v. Georgia, 435 U.S. 223, 239

(1978) (drawing on studies conducted “since

Williams was decided” to conclude 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”).

Numerous empirical studies, including many

conducted post-Williams, confirm that twelvemember juries are markedly better along every

measure Williams found critical. They provide for

more considered deliberations by improving

dissenting jurors’ ability to withstand pressure to

conform to the majority. See Alisa Smith & Michael

J. Saks, The Case for Overturning Williams v.

Florida and the Six-Person Jury: History, Law, and

Empirical Evidence, 60 Fla. L. Rev. 441, 457 (2008).

They more accurately discuss evidence in

deliberations

and

engage

with

probative

information.

See id. at 464-66.

They better

represent a cross-section of the community. See

Shari Seidman Diamond et al., Achieving Diversity

on the Jury: Jury Size and the Peremptory

Challenge, 6 J. Empirical Legal Stud. 425, 438, 442

(2009). And they produce higher-quality verdicts,

including by decreasing the odds that innocent

defendants will be convicted. See Stuart S. Nagel &

Marian Neef, Deductive Modeling to Determine an

Optimum Jury Size and Fraction Required to

Convict, 1975 Wash. U. L.Q. 933, 975.

In short, “Williams was wrong the day it was

decided, it remains wrong today, and it impairs both

the integrity of the American criminal justice system

and the liberties of those who come before our

Nation’s courts.” Khorrami v. Arizona, 143 S. Ct. 22,

23 (2022) (Gorsuch, J., dissenting from denial of

certiorari). The decision of Florida’s Fourth District

Court of Appeal should be reversed.

ARGUMENT

I. At the Founding, Juries Were Composed of

Twelve People.

The jury has always been “justly dear to the

American people[,] . . . an object of deep interest and

solicitude.” Parsons v. Bedford, 28 U.S. (3 Pet.) 433,

446 (1830). Mentioned expressly in three of the first

ten amendments to the Constitution, it is “a

paradigmatic image underlying the original Bill of

Rights,” Amar, supra, at 96; see Miller, supra, at 643;

U.S. Const. amends. V, VI, VII.

The Founding generation’s belief in the jury had

its foundation in English common law, which long

recognized the jury as critical to preserving liberty.

See Richard S. Arnold, Trial by Jury: The

Constitutional Right to a Jury of Twelve in Civil

Trials, 22 Hofstra L. Rev. 1, 13 (1993) (“By the

1600s, when the thirteen colonies were founded, jury

trial had become one of the great palladiums of

English liberty.”); Larry T. Bates, Trial by Jury After

Williams v. Florida, 10 Hamline L. Rev. 53, 53 (1987)

(“[B]y the end of the thirteenth century the jury had

become an important element in English criminal

procedure.”). As William Blackstone emphasized,

“the trial by jury ever has been, and I trust ever will

be, looked upon as the glory of the English law.” 3

Blackstone, Commentaries 379. To Blackstone, trial

by jury was “the most transcendent privilege which

any subject can enjoy, or wish for.” Id.

At common law, a jury was defined in part by the

number of people who served on it: twelve. See, e.g.,

Bates, supra, at 55 (concluding that an “essential

characteristic[] of the petit jury at common law w[as]

the number of persons which comprised the jury—

twelve”). As Blackstone explained, a person could

not be “affected either in his property, his liberty, or

his person, but by the unanimous consent of twelve

of his neighbours and equals.”

3 Blackstone,

Commentaries 379.

Expanding on this point,

Blackstone later commented that it was important

that a trial by jury include “the unanimous suffrage

of twelve of his equals and neighbours, indifferently

chosen, and superior to all suspicion.” 4 Blackstone,

Commentaries 343. Other prominent legal thinkers

of the time similarly embraced the twelve-member

jury. See, e.g., Sir Matthew Hale, The History of the

Common Law of England 256 (1713) (stating that a

jury should be composed of “[t]welve, and no less, of

such as are indifferent”); 3 Matthew Bacon, A New

Abridgement of the Law 234 (3d ed. 1768) (stating

that the “Petty Jury [must consist] of twelve, and

can be neither more nor less”).2

The Framers shared this belief that a “jury”—as

that term was used in the Sixth Amendment’s jurytrial guarantee in criminal cases—was composed of

twelve people. See Arnold, supra, at 5 (“[I]t was a

scholarly axiom at the time the Bill of Rights was

drafted that a jury was comprised of twelve. This

clearly was the understanding of the Founding

Generation . . . .”). Indeed, many colonial charters

Although the origin of the jury’s twelve-person size is

unknown, see Arnold, supra, at 5, that number was well

established prior to the Framing, see id. at 3 (“For over six

hundred years, Western civilization took it for granted that a

jury must be composed of twelve persons.”); id. at 8 (“[A]ny

variation in number ended during the reign of Edward IV

(1461-1483) when the unanimous verdict of twelve

unquestionably and invariably became the law of England,

absent consent of the parties.”).

required that criminal juries be composed of twelve

members. See Miller, supra, at 640 n.115 (noting

that New Hampshire, New York, Pennsylvania,

Plymouth Plantation, Virginia, and West Jersey

“specified that trial by jury in criminal cases meant

trial by a panel of 12 indifferent members of the

community reaching a unanimous verdict”); see also

Wanling Su & Rahul Goravara, What Is a Jury?, 103

N.C. L. Rev. 969, 984 (2025) (explaining that the

Fundamental Constitutions of Carolina required

that “[e]very jury shall consist to twelve men”

(alteration in original) (quoting Fundamental

Constitutions of Carolina, 1669, art. 69, reprinted in

1 Bernard Schwartz, The Bill of Rights: A

Documentary History 108, 118 (1971))); Bates,

supra, at 65-66 (surveying charters of the colonies

and concluding that Constitutional Convention

delegates understood that “trial by jury in criminal

cases meant trial by a body of twelve persons all of

whom agreed to the verdict”).

During the debates on ratifying the Constitution,

Virginia Governor Edmund Randolph questioned

the need for a Bill of Rights, emphasizing as to the

jury right that “the 3d article provide[s] that the

trial of all crimes shall be by jury,” and “[t]here is no

suspicion that less than twelve jurors will be

thought sufficient.” 3 The Debates in the Several

State Conventions on the Adoption of the Federal

Constitution 467 (Jonathan Elliot ed., 1836).

William Pierce, a delegate to the Constitutional

Convention, assumed while discussing “this new

Constitution” that “trial by jury” necessarily meant

a group of “twelve men.” Letter from Hon. William

Pierce to St. George Tucker (Sept. 28, 1787),

reprinted in 3 The Documentary History of the

Ratification of the Constitution: Ratification of the

Constitution by the States 296, 296 (Merrill Jensen

ed., 1978). And as the Sixth Amendment was being

debated and ratified by the states, Justice James

Wilson wrote in his 1790s Lectures on Law that “[t]o

the conviction of a crime, the undoubting and the

unanimous sentiment of the twelve jurors is of

indispensable necessity.” Wilson, supra, at 350.

Moreover, just like the unanimity requirement,

the twelve-person requirement was not “lost to time

and only recently recovered.” Ramos, 590 U.S. at 92.

Across the nineteenth century, this Court, state

supreme courts, and influential legal thinkers all

recognized that “[t]he term jury is well understood

to be twelve men.” Foote v. Lawrence, 1 Stew. 483,

483 (Ala. 1828). In Thompson v. Utah, for example,

this Court asked whether “the jury referred to in the

original Constitution and in the Sixth Amendment

is a jury constituted, as it was at common law, of

twelve persons, neither more nor less,” and

answered that question in the affirmative. 170 U.S.

at 349; see Williams, 399 U.S. at 122 (Harlan, J.,

concurring in the result in Williams, 399 U.S. 78,

and dissenting in Baldwin v. New York, 399 U.S. 66

(1970)) (“[B]efore [Williams,] it would have been

unthinkable to suggest that the Sixth Amendment’s

right to a trial by jury is satisfied by a jury of six.”).

Similarly, New Hampshire’s highest court explained

that the term “jury” has been “well known in the

language of the law,” such that it was “used at the

adoption of the constitution, and always, it is

believed, before that time, and almost always since,

in a single sense. A jury for the trial of a cause was

a body of twelve men.” Op. of the Justices of the

Supreme Jud. Ct., 41 N.H. 550, 551 (1860); see

Cancemi v. People, 18 N.Y. 128, 138 (1858) (“It would

be a highly dangerous innovation, in reference to

criminal cases, upon the ancient and invaluable

institution of trial by jury . . . for the court to allow

of any number short of a full panel of twelve jurors

. . . .”); State v. Everett, 14 Minn. 439, 444 (1869)

(“The word ‘jury’ . . . imports a body of twelve men.”).

Justice Joseph Story embraced this requirement

in his Commentaries on the Constitution. First, he

explained that the forebears of the United States

“brought this great privilege [of the jury trial] with

them, as their birthright and inheritance, as part of

that admirable common law.” 2 Joseph Story,

Commentaries on the Constitution of the United

States § 1779, at 559 (5th ed. 1891). He then went

on to explain that “[a] trial by jury is generally

understood to mean ex vi termini [i.e., by definition],

a trial by a jury of twelve men, impartially selected,

who must unanimously concur in the guilt of the

accused before a legal conviction can be had. Any

law, therefore, dispensing with any of these

requisites, may be considered unconstitutional.” Id.

at 559 n.2.

In the early twentieth century, this Court

repeatedly emphasized that “there can be no doubt”

that “a jury composed, as at common law, of twelve

jurors was intended by the Sixth Amendment to the

Federal Constitution.” Maxwell v. Dow, 176 U.S.

581, 586 (1900); see Patton v. United States, 281 U.S.

276, 288-90 (1930) (recognizing that the “common

law elements” of a jury, including that the “jury

should consist of twelve men, neither more nor less

. . . are embedded in” the Sixth Amendment);

Rassmussen v. United States, 197 U.S. 516, 528

(1905) (holding that a statute permitting six-person

juries in Alaska was unconstitutional); id. at 529

(Harlan, J., concurring) (“The constitutional

requirement that ‘the trial of all crimes . . . shall be

by jury,’ means, as this court has adjudged, a trial

by the historical, common-law jury of twelve

persons.”); see also Williams, 399 U.S. at 117

(Marshall, J., dissenting in part) (highlighting an

“unbroken line of precedent going back over 70

years” confirming that “the jury guaranteed by the

Sixth Amendment consists of twelve persons”

(quotation marks omitted)).

And in more recent cases, this Court has

repeatedly observed that the Sixth Amendment’s

jury-trial guarantee includes the right to a twelvemember jury. In Blakely v. Washington, this Court

explained that the “longstanding tenets of commonlaw criminal jurisprudence” underlying the Sixth

Amendment include the rule “that the ‘truth of every

accusation’ against a defendant ‘should afterwards

be confirmed by the unanimous suffrage of twelve of

his equals and neighbours.’” 542 U.S. 296, 301

(2004) (quoting 4 Blackstone, Commentaries 343).

This Court also affirmed that principle in

Apprendi v. New Jersey, explaining that to “‘guard

against a spirit of oppression and tyranny on the

part of rulers,’ and ‘as the great bulwark of [our] civil

and political liberties,’ trial by jury has been

understood to require that ‘the truth of every

accusation . . . be confirmed by the unanimous

suffrage of twelve of [the defendant’s] equals and

neighbours.’” 530 U.S. 466, 477 (2000) (alterations

except ellipsis in original) (twice quoting 2 Joseph

Story, Commentaries on the Constitution of the

United States §§ 1779-80, at 540-41 (4th ed. 1873);

and then quoting 4 Blackstone, Commentaries 343);

see United States v. Booker, 543 U.S. 220, 238-39

(2005) (same); see also Apprendi, 530 U.S. at 498

(Scalia, J., concurring) (observing that a defendant’s

guilt must be “determined beyond a reasonable

doubt by the unanimous vote of 12 of his fellow

citizens” (emphasis omitted)).

And, finally, many of the historical sources this

Court cited in Ramos to show that jury decisions

must be unanimous also confirmed that a jury must

consist of twelve people. See, e.g., Ramos, 590 U.S.

at 90 (quoting 4 Blackstone, Commentaries 343).

Those sources emphasize that a “‘verdict, taken from

eleven, was no verdict’ at all.” Id. (quoting Thayer,

supra, at 88-89 n.4). And they underscore that “a

defendant enjoys a ‘constitutional right to demand

that his liberty should not be taken from him except

by the joint action of the court and the unanimous

verdict of a jury of twelve.’” Id. at 92 (quoting

Thompson, 170 U.S. at 351).

This Court has thus repeatedly recognized what

history from the Framing makes clear: the “sacred

bulwark of liberty,” 4 Blackstone, Commentaries

344, that the Framers codified in the Sixth

Amendment was the jury that existed at common

law—a jury of twelve of the defendant’s “equals and

neighbours,” Apprendi, 530 U.S. at 477 (quotation

marks omitted). That history is the proper lodestar

for determining the meaning of the Amendment’s

jury-trial guarantee, as the next Section describes.

II. The Williams Court Improperly Dismissed

the Sixth Amendment’s History in

Determining Its Meaning.

Williams expressly rejected the relevance of the

jury’s common-law history to determining the scope

of the Sixth Amendment’s jury right. Despite

recognizing that “[i]t may well be that the usual

expectation was that the jury would consist of 12,”

Williams, 399 U.S. at 98, the Williams Court

concluded that “there is absolutely no indication in

‘the intent of the Framers’ of an explicit decision to

equate the constitutional and common-law

characteristics of the jury,” id. at 99.

But Williams “was wrong the day it was decided,

it remains wrong today,” and its approach is at odds

with this Court’s more recent Sixth Amendment

cases. Khorrami, 143 S. Ct. at 23 (Gorsuch, J.,

dissenting from denial of certiorari). The Williams

Court relied primarily on evidence from the drafting

of the Sixth Amendment to support its conclusion

that the Framers did not intend to embed the

essential common-law features of the jury in the

Constitution, observing that “provisions spelling out

such common-law features of the jury as ‘unanimity,’

or ‘the accustomed requisites’” that appeared in

James Madison’s original draft were omitted from

the final version. Williams, 399 U.S. at 93-96. But

this Court later expressly rejected that reasoning in

Ramos, pointing out that this interpretation of the

drafting process essentially blinds the Court to

“everything history might have taught us about what

it means to have a jury trial,” which would “leave the

right to a ‘trial by jury’ devoid of meaning.” Ramos,

590 U.S. at 98. Indeed, such deletions “just as easily

support” the inference that the excised language was

deemed superfluous in light of the well-understood

meaning of the term “jury” at common law. Id. at

97; see Williams, 399 U.S. at 123 n.9 (Harlan, J.,

concurring in the result in Williams, 399 U.S. 78,

and dissenting in Baldwin, 399 U.S. 66) (noting that

“a more likely explanation of the Senate’s action is

that it was streamlining the Madison version on the

assumption that the most prominent features of the

jury would be preserved as a matter of course”).

Based on its faulty interpretation of the Sixth

Amendment’s drafting process, the Williams Court

“turn[ed] to other than purely historical

considerations to determine which features of the

jury system, as it existed at common law, were

preserved in the Constitution.” Williams, 399 U.S.

at 99. According to Williams, “[t]he relevant inquiry

. . . must be the function that the particular [jury]

feature performs and its relation to the purposes of

the jury trial.” Id. at 99-100 (emphasis added). That

inquiry necessarily privileges a functional approach

to determining constitutional meaning, unmoored

from the text and history of the Sixth Amendment’s

jury-trial guarantee.

But taking such an approach is at sharp odds

with this Court’s more recent Sixth Amendment

jurisprudence. As this Court declared in Ramos,

“[w]hen the American people chose to enshrine [the

jury-trial] right in the Constitution, they weren’t

suggesting fruitful topics for future cost-benefit

analyses.” Ramos, 590 U.S. at 100. And it is not this

Court’s role to “reassess” whether the right to a

twelve-person jury is “‘important enough’ to retain.”

Id. Instead, the Sixth Amendment requires a

reviewing court to determine what, “at the time of

the Sixth Amendment’s adoption, the right to trial

by jury included.” Id. (emphasis omitted).

Indeed, long before Ramos, this Court recognized

that the Sixth Amendment’s scope is defined by its

original meaning, not a free-floating functional

analysis. In this vein, Apprendi confirmed that “the

historical foundation for our recognition of [the Sixth

Amendment jury right] extends down centuries into

the common law,” 530 U.S. at 477, which requires

careful inquiry into the common law as it existed at

the Framing to answer questions about the

Amendment’s meaning, see id. at 478-83.

Moreover, as this Court explained in Giles v.

California when addressing the scope of the

Confrontation Clause, courts may not “extrapolate

from the words of the Sixth Amendment to the

values behind it, and then . . . enforce its guarantees

only to the extent they serve (in the courts’ views)

those underlying values.” 554 U.S. 353, 375 (2008).

Instead, “[t]he Sixth Amendment seeks fairness

indeed—but seeks it through very specific means . . .

that were the trial rights of Englishmen.” Id.; see

Crawford v. Washington, 541 U.S. 36, 43-50 (2004)

(looking to “historical background,” including

common law and early state practice, to determine

the Confrontation Clause’s meaning).

And in

holding that factors that increase a defendant’s

sentence must be proven to a jury beyond a

reasonable doubt, this Court has emphasized that

what matters is not “whether or to what degree trial

by jury impairs the efficiency or fairness of criminal

justice,” but rather “the Framers’ paradigm for

criminal justice.” Blakely, 542 U.S. at 313.

Since this Court overruled Apodaca in 2020,

Williams stands alone in rejecting the relevance of

Sixth Amendment history to determining the

meaning of the Amendment’s jury-trial guarantee.

Both the Sixth Amendment’s history and this

Court’s more recent decisions make clear that

Williams erred in concluding that a criminal jury

could have fewer than twelve members. But even if

Williams’s reliance on an ahistorical functionalist

analysis were correct (which it is not), that decision

should still be overruled because, as the next Section

discusses, empirical research belies the conclusion

that juries of fewer than twelve people are

functionally equivalent to twelve-person juries.

III. Empirical Research Shows that Juries of

Fewer than Twelve People Undermine the

Right to a Fair Trial Guaranteed by the

Sixth Amendment.

Even if this Court maintains the functionalist

approach applied (improperly) in Williams, it should

still conclude that twelve-person juries are a

constitutional floor. Williams assessed the effect of

jury size along three primary dimensions: first, the

quality of jury deliberations; second, the jury’s

ability to represent a cross-section of the community;

and third, the quality of jury verdicts. See Williams,

399 U.S. at 100-02. But the so-called “‘experiments’”

on which Williams relied amounted to little more

than “conclusory statements . . . supported at best by

limited experience and anecdote.” Higginbotham et

al., supra, at 51-52 (quoting Williams, 399 U.S. at

101); see Zeisel, supra, at 713-15. Even at the time,

those “experiments” did not support the conclusions

the Williams Court drew and, since then, further

research has confirmed that juries smaller than

twelve are worse in every regard Williams identified

as essential to the Sixth Amendment’s fair-trial

guarantee. See, e.g., Su & Goravara, supra, at 1013,

1019-28

(collecting

empirical

research

demonstrate that six-person juries are not

“functionally equivalent” to twelve-person juries).

A. Deliberation Quality

Williams was not entirely clear about the factors

it understood to “promote group deliberation,” 399

U.S. at 100, but it suggested that the ability of a

dissenting juror to withstand pressure to conform to

the majority’s view was important, see id. at 101

n.49. Williams reasoned that an “operative factor[]”

influencing dissenting jurors’ willingness to conform

to majority pressure during deliberation is the

“proportional size of the majority aligned against

them,” id., such that “a minority faction in a jury

divided 10-2 would be no better able to withstand

majority influence than the minority faction in a

jury divided 5-1,” Smith & Saks, supra, at 457.

But the empirical studies Williams cited to

support this proposition “found exactly the

opposite.” Id. They showed that if a dissenter has

just one attitudinal ally, that dissenter is far more

likely to resist pressure to conform; in contrast, a

lone dissenter can be convinced by an otherwise

unanimous majority to “disbelieve his own correct

observation.” Id. (quoting Harry Kalven, Jr. & Hans

Zeisel, The American Jury 463 (1966)). Because

twelve-person juries are more likely to have multiple

dissenting members, see Zeisel, supra, at 722-23,

they improve dissenters’ ability to resist majority

pressure, minimizing the risk of erroneous decisions

reached by dint of sheer numbers and thus making

way for more considered jury deliberations.

Research conducted since Williams confirms that

twelve-person juries are more deliberative in other

ways as well: they more accurately discuss evidence

in deliberation, rely on more probative information,

and better recall such information. See Smith &

Saks, supra, at 465 (collecting studies). In one

analysis, researchers reported that twelve-person

juries discussed trial testimony more accurately

than did their six-person counterparts. See Michael

J. Saks & Mollie Weighner Marti, A Meta-Analysis

of the Effects of Jury Size, 21 L. & Hum. Behav. 451,

458-59 (1997). Another study found that twelveperson juries “recall[ed] more probative evidence

and relied less on nonprobative items” than did sixperson juries. Irwin A. Horowitz & Kenneth S.

Bordens, The Effects of Jury Size, Evidence

Complexity, and Note Taking on Jury Process and

Performance in a Civil Trial, 87 J. Applied Psych.

121, 128 (2002).

These findings are consistent with socialpsychology research explaining that larger groups

perform better at decision-making because they can

marshal more resources than smaller groups. See

Saks & Marti, supra, at 458 (citing Ivan D. Steiner,

Group Process and Productivity (1972)); see also

Ballew, 435 U.S. at 232-33 (“Generally, a positive

correlation exists between group size and the quality

of both group performance and group productivity.”).

Larger juries may also be more sensitive to factual

ambiguities than smaller juries. See Angelo Valenti

& Leslie Downing, Six Versus Twelve Member

Juries: An Experimental Test of the Supreme Court

Assumption of Functional Equivalence, 1 Pers. &

Soc. Psych. Bull. 273, 274 (1974).

Research further indicates that larger juries

deliberate longer than smaller ones. Eleven studies

examined in a meta-analysis compared the length of

deliberations between large and small juries, and all

but one found larger juries deliberated longer. See

Saks & Marti, supra, at 457-58. “The mean time

difference for studies of actual juries . . . is forty-four

minutes.” Smith & Saks, supra, at 465. Longer

deliberation time is suggestive of “more substantive

deliberation,” including “the sharing of more facts,

more ideas, and more challenges to the tentative

conclusions of others.” See Saks & Marti, supra, at

458.

B. Community Representativeness

Williams recognized that an “essential feature of

a jury obviously lies . . . in the community

participation and shared responsibility that results

from that group’s determination of guilt or

innocence.” 399 U.S. at 100; see Ballew, 435 U.S. at

237 (“It is part of the established tradition in the use

of juries as instruments of public justice that the

jury be a body truly representative of the

community.” (quoting Smith v. Texas, 311 U.S. 128,

130 (1940))). But it dismissed as “unrealistic” the

concern that representation “will be significantly

diminished” by reducing the size of juries to six.

Williams, 399 U.S. at 102.

Williams’s assumptions on this point, however,

contradict basic “principles of statistical sampling”

that were well known at the time. Smith & Saks,

supra, at 458; see Zeisel, supra, at 716. These

principles make clear that increasing a sample’s size

necessarily increases the likelihood that it will

contain “populations of any given stratification.”

Smith & Saks, supra, at 458. To illustrate, in

randomly impaneled six- and twelve-person juries

from a population in which 10% hold a minority

viewpoint (or demographic identity), over half of sixperson juries will contain no minority member,

while fewer than a third of twelve-person juries will

lack minority representation. See Zeisel, supra, at

716.

Empirical findings confirm that six-person juries

lack minority members much more frequently than

twelve-person juries do. A meta-analysis of studies

found overwhelming support for the proposition that

twelve-person juries are more representative than

six-person juries. See Saks & Marti, supra, at 45557. The authors concluded that the “effect of jury

size on minority representation is highly

significant,” with the “effect of reduced jury size . . .

equivalent to a decrease in the opportunity of

[minority] representation from about 63-64% to

about 36-37%.”

Id. at 457.

“Not one study

contradicted this result.” Smith & Saks, supra, at

464.

A more recent study further strengthens these

findings. Researchers analyzed data from 277 civil

trials between 2001 and 2007: 89 with six-person

juries and 188 with twelve-person juries. See

Diamond et al., supra, at 434-35. Although Black

potential jurors comprised 25% of the venire before

and after peremptory challenges, see id. at 443,

28.1% of impaneled six-person juries lacked even a

single Black juror compared to only 2.1% of twelveperson juries, see

id.

442.

This

underrepresentation is not “simply proportional,

which would occur if juries of both sizes were equally

likely” to include a Black juror; instead, “58.3

percent of six-member juries had one-sixth or fewer

black jurors, while 37.7 percent of 12-member juries

had one-sixth or fewer black jurors.” Id. at 442.

Importantly, it is jury size, not “patterns in the

exercise of [peremptory] juror challenges, [that]

accounts for this pattern.” Id. at 443.

Of course, the specific “impact of jury size on . . .

minority representation is affected by the

percentage of minorities on the venire.” Id. The

same study also examined a proportionally smaller

cohort of Hispanic venirepersons, finding that 66.3%

of impaneled six-person juries lacked any Hispanic

juror compared to 40.4% of twelve-person juries. Id.

at 444. And just 9.0% of six-person juries included

at least two Hispanic jurors compared to 25.5% of

twelve-person juries. Id. Such underrepresentation

“would emerge for any minority,” whether

demographic, attitudinal, or otherwise. Id. at 445.

The effects of jury size on cross-sectional

representation carry extra weight because Black

jurors, in particular, are “vastly overrepresented” as

dissenting jurors urging acquittal. Thomas Ward

Frampton, The Jim Crow Jury, 71 Vand. L. Rev.

1593, 1599 (2018) (analyzing 199 felony verdicts by

“racially mixed, nonunanimous juries”). That fact is

especially significant when combined with the

findings discussed above that show a dissenter’s

propensity to conform to majority pressure

decreases in the presence of at least one attitudinal

ally. See Smith & Saks, supra, at 457.

C. Verdict Quality

Williams claimed that “[w]hat few experiments

have occurred . . . indicate that there is no

discernible difference between the results reached

by” six- and twelve-member juries. 399 U.S. at 101;

see id. at 100-01 (“[T]he reliability of the jury as a

factfinder hardly seems likely to be a function of its

size.”). Once again, that proposition was wrong.

To begin, “not one of [the] ‘experiments’”

Williams cited “provide[s] any evidence on the

question at hand.” Smith & Saks, supra, at 455-56

(quoting Williams, 399 U.S. at 101) (cataloging and

critiquing as inapt each source cited by footnote 48

of Williams to support its claim that different-sized

juries reach indistinguishable results); see David F.

Walbert, The Effect of Jury Size on the Probability of

Conviction: An Evaluation of Williams v. Florida, 22

Case W. Rsrv. L. Rev. 529, 535 (1971) (“[T]he

references cited do not support this conclusion.”).

And the claim is contradicted by published

studies: there are “discernible differences” between

the results reached by juries of six and juries of

twelve. When such results “diverge,” for example,

verdicts from twelve-member juries are “likely to be

of somewhat higher quality” and “superior with

respect to other important values.” Richard O.

Lempert, Uncovering “Nondiscernible” Differences:

Empirical Research and the Jury-Size Cases, 73

Mich. L. Rev. 643, 698 (1975) (emphasis omitted).

Other “serious differences” include the fact that

jury size “significantly affects the likelihood of

conviction.” Walbert, supra, at 547 (noting that “the

Court’s conclusion that both [six- and twelvemember] juries would return the same verdict is

erroneous”). More specifically, researchers report

that “the probability of an innocent person’s being

convicted increases . . . as the jury size decreases.”

Nagel & Neef, supra, at 975; see Brown v. Louisiana,

447 U.S. 323, 332 (1980) (“[A] decline in jury size

leads to less accurate factfinding and a greater risk

of convicting an innocent person.”); cf. Angelo C.

Valenti & Leslie L. Downing, Differential Effects of

Jury Size on Verdicts Following Deliberation as a

Function of the Apparent Guilt of a Defendant, 32 J.

Pers. & Soc. Psych. 655, 662 (1975). And although

“smaller juries may result in certain economies, by

reducing the odds of a hung jury it may do so at the

defendant’s expense.” Norbert L. Kerr & Robert J.

MacCoun, The Effects of Jury Size and Polling

Method on the Process and Product of Jury

Deliberation, 48 J. Pers. & Soc. Psych. 349, 360

(1985); see Ballew, 435 U.S. at 236 (noting that “the

number of hung juries would diminish as the panels

decreased in size”). As this Court has recognized,

criminal verdicts “vary as juries become smaller,

and . . . the variance amounts to an imbalance to the

detriment of one side, the defense.” Id.

***

In sum, the central premises undergirding

Williams were unsupported originally—and have

been further undermined by later legal and factual

developments. This Court should reject Williams’s

anomalous holding. Doing so will restore coherence

to this Court’s Sixth Amendment jurisprudence and

protect the “sacred bulwark” of the jury.

CONCLUSION

For the foregoing reasons, this Court should

reverse the decision of Florida’s Fourth District

Court of Appeal.

Respectfully submitted,

ELIZABETH B. WYDRA

BRIANNE J. GOROD*

JOSHUA D. BLECHER-COHEN

CONSTITUTIONAL

ACCOUNTABILITY CENTER

1730 Rhode Island Ave. NW, Suite 1200

Washington, D.C. 20036

(202) 296-6889

brianne@theusconstitution.org

Counsel for Amicus Curiae

August 13, 2026

*Counsel of Record

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.