Amicus Curiae Brief — Mark Todd Minor, Petitioner v. Florida

No. 24-7489

In The

Supreme Court of the United States

MARK TODD MINOR,

Petitioner,

v.

STATE OF FLORIDA,

Respondent.

On Petition for a Writ of Certiorari

to the Fourth District Court of Appeal of Florida

BRIEF AMICUS CURIAE OF

CONSTITUTIONAL ACCOUNTABILITY

CENTER IN SUPPORT OF PETITIONER

ELIZABETH B. WYDRA

BRIANNE J. GOROD*

ANA M. BUILES

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 25, 2025

* Counsel of Record

i

TABLE OF CONTENTS

Page

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

ii

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

1

INTRODUCTION AND SUMMARY

OF ARGUMENT ................................................

1

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

6

I.

At the Founding, Juries Were Composed

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

6

II.

The Williams Court Improperly

Dismissed the History of the Sixth

Amendment in Determining Its

Meaning.......................................................

13

III. Empirical Research Demonstrates that

Juries of Fewer Than Twelve People

Undermine the Right to a Fair Trial

Guaranteed by the Sixth Amendment .......

16

A. Thoroughness of Deliberations ........

16

B. Representativeness of the

Community .......................................

18

C. Reliability of Verdicts ......................

20

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

22

ii

TABLE OF AUTHORITIES

Page(s)

Cases

Apodaca v. Oregon,

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

Apprendi v. New Jersey,

530 U.S. 466 (2000) .............................

2

10, 14

Baldwin v. New York,

399 U.S. 117 (1970) .................................. 9, 13

Ballew v. Georgia,

435 U.S. 223 (1978) .................................. 5, 18

Blakely v. Washington,

542 U.S. 296 (2004) .................................. 11, 15

Cancemi v. People,

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

10

Crawford v. Washington,

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

15

Foote v. Lawrence,

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

9

Giles v. California,

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

15

Khorrami v. Arizona,

143 S. Ct. 22 (2022) ..................................... 6, 13

Maxwell v. Dow,

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

11

Opinion of Justices,

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

10

iii

TABLE OF AUTHORITIES – cont’d

Page(s)

Parsons v. Bedford,

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

6

Patton v. United States,

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

11

Ramos v. Louisiana,

590 U.S. 83 (2020) ........................ 2-4, 9, 12, 14

Rassmussen v. United States,

197 U.S. 516 (1905) .....................................

11

State v. Everett,

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

10

Thompson v. Utah,

170 U.S. 343 (1898) .............................. 3, 10, 12

United States v. Booker,

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

12

Williams v. Florida,

399 U.S. 78 (1970) .... 4, 5, 11, 13, 14, 16-18, 21

Constitutional Provisions

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

7

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

7

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

7

Books, Articles, and Other Authorities

Akhil Reed Amar, The Bill of Rights: Creation

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

iv

TABLE OF AUTHORITIES – cont’d

Page(s)

Shamena Anwar et al., The Impact of Jury Race

in Criminal Trials, 127 Q. J. Econ. 1017

(2012) ........................................................... 20

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

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

Florida, 10 Hamline L. Rev. 53 (1987) ....... 7, 8

3 William Blackstone, Commentaries on the

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

4 William Blackstone, Commentaries on the

Laws of England (1769) ............... 1, 3, 7, 11, 12

3 The Debates in the Several State Conventions

on the Adoption of the Federal Constitution

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

9

Shari Seidman Diamond et al., Achieving Diversity on the Jury: Jury Size and the Peremptory

Challenge, 6 J. Empirical Legal Stud. 425

(2009) .................................................... 6, 19, 20

Thomas Ward Frampton, The Jim Crow Jury,

71 Vand. L. Rev. 1593 (2018) ..................... 20

2 Sir Matthew Hale, The History of the Common

Law (1713)...................................................

8

Patrick E. Higginbotham, Lee H. Rosenthal &

Steven S. Gensler, Better By the Dozen: Bringing Back the Twelve-Person Civil Jury,

104 Judicature 47 (2020) ............................ 5, 16

v

TABLE OF AUTHORITIES – cont’d

Page(s)

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) .................................................... 6, 17, 21

Robert H. Miller, Comment, 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, 8

Michael J. Saks & Mollie Weighner Marti, A

Meta-Analysis of the Effects of Jury Size,

21 L. & Hum. Behav. 451

(1997) ................................................. 17-19, 21

Alisa Smith & Michael J. Saks, In Honor of Walter O. Weyrauch: The Case for Overturning

Williams v. Florida and the Six-Person Jury:

History, Law, and Empirical Evidence,

60 Fla. L. Rev. 441 (2008) ................

6, 17-21

2 Joseph Story, Commentaries on the Constitution of the United States § 1779

(5th ed. 1891) ........................................... 10, 11

Wanling Su & Rahul Goravara, What is a Jury,

103 N.C. L. Rev. 969 (2025) ..................... 9, 16

James Thayer, Evidence at the Common Law

(1898) ........................................................ 3, 12

vi

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 Personality

& Soc. Psych Bull. 273 (1974).................

21

2 James Wilson, Works of the Honourable James

Wilson (1804)............................................ 3, 9

Hans Zeisel, And Then There Were None: The

Diminution of the Federal Jury, 38 U. Chi.

L. Rev. 710 (1971) ................... 5, 16, 17, 19, 21

1

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. Sir William

Blackstone, for example, called the jury a “sacred

bulwark” of liberty. 4 William Blackstone, Commentaries on the Laws of England 344 (1769) [hereinafter Blackstone’s Commentaries]. To Blackstone, “the

1 Counsel for all parties received notice at least 10 days

prior to the due date of amicus’s intention to file this brief.

Amicus states that 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 the preparation or submission of

this brief. No person other than amicus or its counsel made a

monetary contribution to its preparation or submission.

2

most 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 id. at 379 (1768).

Drawing on that history, this Court has held that

the Sixth Amendment, as incorporated by the Fourteenth Amendment, guarantees criminal defendants

in both state and federal courts the right to a unanimous jury verdict. Ramos v. Louisiana, 590 U.S. 83,

93 (2020). This Court looked to “the common law,

state practices at the founding era, [and] opinions

and treatises written soon after,” and concluded that

at the time of the Sixth Amendment’s adoption,

“trial by an impartial jury” meant that “[a] jury must

reach a unanimous verdict in order to convict.” Id.

at 89.

In so holding, this Court overruled a 1972 decision, Apodaca v. Oregon, 406 U.S. 404 (1972), which

permitted states to convict criminal defendants on

the basis of non-unanimous jury verdicts. Apodaca

was premised on the view that the unanimity requirement did not serve “an important function in

contemporary society.” Ramos, 590 U.S. 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

analysis that was also deeply flawed on its own

terms. Id. at 100.

The same history and reasoning that led this

Court to overrule Apodaca and hold that the Sixth

Amendment requires jury unanimity compels the

conclusion that the Sixth Amendment also requires

that a jury consist of at least twelve people. When

3

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, Comment, 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, at

the same time the Sixth Amendment was being ratified by the states, Justice James Wilson wrote 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) (emphasis

added). Thus, the jury right that the Framers enshrined in the Bill of Rights was 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 no fewer than 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 neighbors.’”

Ramos, 590 U.S. at 90 (quoting 4 Blackstone’s Commentaries 343 (1769)) (alterations adopted) (emphasis added). Another provided that “a ‘verdict, taken

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

James Thayer, Evidence at the Common Law 88-89

n.4 (1898)). And yet another 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 twelve persons.’” Id. at 92 (emphasis added)

(quoting Thompson v. Utah, 170 U.S. 343, 351

(1898)).

4

Despite this long history confirming that juries

consisted of at least twelve people at the time of the

Framing, Mark Todd Minor was convicted of serious

crimes by a jury composed of only six members and

was effectively sentenced to life in prison as a result.

Pet. 4, 35; see also Pet. App. 49a. This was possible

only because this Court in Williams v. Florida, 399

U.S. 78 (1970), allowed juries composed of as few as

six people to convict criminal defendants. But the

same problems that doomed Apodaca plague Williams. Decided only two years before Apodaca, Williams dismissed the long history confirming that the

size of a jury has been fixed at twelve for some seven

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.

The Williams Court rejected the common law history underlying the Sixth Amendment just like the

Apodaca Court did, and it was just as wrong to do so.

Applying this Court’s reasoning in Ramos, it is inappropriate to conduct a “functionalist analysis” 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 the Apodaca Court relied on in justifying its decision, the evidence the Williams Court pointed to drastically understated the deficiencies of smaller juries.

5

According to Williams, smaller juries engage in deliberations that are just as good as those of larger

juries, smaller juries are just as capable of representing a fair cross-section of the community as

larger ones, and smaller juries produce verdicts that

are just as reliable. Williams, 399 U.S. at 101-02.

But as this Court recognized as early as 1978 in

Ballew v. Georgia, 435 U.S. 223 (1978), and as empirical research since then has confirmed, all of

these claims are wrong. Id. at 239 (examining empirical research and concluding that “the purpose

and functioning of the jury in a criminal trial is seriously impaired, and to a constitutional degree” by

progressively smaller juries).

Williams relied on the “few experiments” it could

find on the effect of jury size on the quality and reliability of verdicts, 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 47, 52 (2020). Instead, they were merely “conclusory statements . . . supported at best by limited

experience and anecdote.” Id. And those conclusory

statements are belied by “well established elementary statistical theory” that was known 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).

Moreover, numerous empirical studies have been

conducted since then confirming that twelve-member juries are markedly better along every measure

Williams found critical: they provide for more considered jury deliberations by improving dissenting

jurors’ ability to withstand pressure to conform to

the majority, Alisa Smith & Michael J. Saks, In

6

Honor of Walter O. Weyrauch: 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

facts in deliberations and rely on more probative information, id. at 465; they better represent a crosssection of the community, see, e.g., Shari Seidman

Diamond et al., Achieving Diversity on the Jury:

Jury Size and the Peremptory Challenge, 6 J. Empirical Legal Stud. 425, 434-35 (2009); and they produce more reliable verdicts, see, e.g., 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, 126 (2002).

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). This Court should grant certiorari.

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). Featured expressly in three of the first

ten amendments to the Constitution, it is “a paradigmatic image underlying the original Bill of

7

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 had

long recognized the jury as critical to the preservation of liberty. See, e.g., 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 Sir 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’s Commentaries 379 (1768). To

Blackstone, trial by jury was “the most transcendent

privilege which any subject can enjoy, or wish for.”

Id.

A defining attribute of the jury as it existed at

common law was that it consisted of twelve people.

See Bates, supra, at 55 (an “essential characteristic[]

of the petit jury at common law [was] the number of

persons which comprised the jury—twelve”). As

Blackstone explained it, 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’s Commentaries 379 (1768). 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 id. at 343

(1769). Other prominent legal thinkers of the time

8

similarly embraced the twelve-member jury. See,

e.g., 2 Sir Matthew Hale, The History of the Common

Law 256 (1713) (stating that a jury should be composed of “[t]welve, and no less, of such as are indifferent”); Bates, supra, at 64 (“In 1736 Bacon wrote

that the petit jury must consist of twelve ‘and can be

neither more nor less.’” (citation omitted)).2

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

that term was used in the Sixth Amendment’s guarantee of a right to trial by jury 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 composed of

twelve. This clearly was the understanding of the

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

charters required that criminal juries be composed

of 12 members. Miller, supra, at 640 n.115 (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

2 Although the precise origins of the number twelve remain

unknown, see Arnold, supra, at 5, there is widespread agreement that the number was well-established prior to the Framing, see, e.g., 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.”). And just

because the reason for this number remains unknown, that

does not mean it was an accident. See Zeisel, supra, at 712

(noting that it “might be more than an accident that after centuries of trial and error the size of the jury at common law came

to be fixed at twelve,” and hypothesizing that “twelve would be

the number that optimizes the jury’s two conflicting goals—to

represent the community and remain manageable”).

9

reaching a unanimous verdict”); see also Wanling Su

& Rahul Goravara, What is a Jury, 103 N.C. L. Rev.

969, 984 (2025) (the “Fundamental Constitutions of

Carolina,” adopted in 1669, required that “[e]very

jury shall consist to twelve men”); Bates, supra, at

66 (surveying charters of the colonies and concluding

that the delegates to the Constitutional Convention

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 ratification debates, Governor Edmund Randolph questioned the need for a Bill of

Rights, noting with respect 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). And as the Sixth Amendment was

being debated and ratified by the states, Justice

James Wilson wrote in his 1790-91 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

(emphasis added).

Moreover, much like the unanimity requirement,

the twelve-person requirement was not “lost to time

and only recently recognized.” Ramos, 590 U.S. at

92. Throughout 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

10

common law, of twelve persons, neither more nor

less,” and answered that question in the affirmative.

170 U.S. at 349; cf. Baldwin v. New York, 399 U.S.

117, 122 (1970) (Harlan, J., dissenting) (“[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, the

New Hampshire Supreme Court explained that the

term “jury” has been “well known in the language of

the law,” and 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.”

Opinion of Justices, 41 N.H. 550, at *1 (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 1833 Commentaries on the Constitution. First,

he explained that America’s forbearers “brought this

great privilege [of trial by jury] 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 . . . , 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 n.2 (emphasis

in original).

11

In the early twentieth century, this Court repeatedly recognized 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) (the “common law elements” of a jury,

including that the “jury should consist of twelve”

people, “are embedded in” the Sixth Amendment);

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

(1905) (holding that a statute allowing for 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) (noting that an “unbroken line of precedent going back over 70 years” recognized 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 twelve-member

jury. In Blakely v. Washington, 542 U.S. 296 (2004),

this Court explained that the “longstanding tenets

of common-law criminal jurisprudence” that the

Sixth Amendment embodies 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 neighbors.’” Id.

at 301 (quoting 4 Blackstone’s Commentaries 343

(1769)).

This Court reaffirmed this principle in Apprendi

v. New Jersey, 530 U.S. 466 (2000), explaining that

“‘to guard against a spirit of oppression and tyranny

12

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 . . . should afterwards be confirmed by the

unanimous suffrage of twelve of [the defendant’s]

equals and neighbours.’” Id. at 477; see id. at 498

(Scalia, J., concurring) (charges must be determined

“beyond a reasonable doubt by the unanimous vote

of 12 of his fellow citizens”); see also United States v.

Booker, 543 U.S. 220, 238-39 (2005) (same).

And in Ramos, this Court cited historical precedents confirming that jury decisions must be unanimous, many of which also confirmed that the jury

must consist of twelve people. According to this

Court, “‘the truth of every accusation . . . should . . .

be confirmed by the unanimous suffrage of twelve of

his equals and neighbors,’” Ramos, 590 U.S. at 90

(quoting 4 Blackstone’s Commentaries 343 (1769))

(alterations adopted); “a ‘verdict, taken from eleven,

was no verdict’ at all,” id. (quoting Thayer, supra, at

88-89 n.4); and “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).

Thus, this Court has repeatedly recognized what

Framing-era history makes clear: the “sacred bulwark of liberty” 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 place

to look to determine the meaning of the Sixth

Amendment, as the next Section demonstrates.

13

II. The Williams Court Improperly Dismissed

the History of the Sixth Amendment in Determining Its Meaning.

The Williams Court expressly rejected the relevance of history to determining the meaning of the

Sixth Amendment. While 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, Williams 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 Court in 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 the common law in the Constitution, noting that “provisions spelling out such common-law features of the jury as ‘unanimity’ or ‘the

accustomed requisites’” that appeared in Madison’s

original draft were omitted from the final version.

Williams, 399 U.S. at 93-96. But this Court expressly rejected that reasoning in Ramos, pointing

out that this interpretation of the drafting history

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, these deletions “just as easily support” the inference that the language was unnecessary in light

of the well-understood meaning of the term “jury” at

common law. Id. at 97; see Baldwin, 399 U.S. at 123

14

n.9 (Harlan, J., dissenting) (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 drafting

history, the Williams Court then decided to “turn[]

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 feature performs and its relation to the purposes of the jury trial.” Id. at 99100.

This approach to the Sixth Amendment inquiry

cannot be reconciled with this Court’s more recent

Sixth Amendment jurisprudence. As this Court put

it 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,” and this Court’s role is not to

“reassess” whether the right to a twelve-person jury

is “‘important enough’ to retain.” Ramos, 590 U.S.

at 100.

Indeed, long before Ramos, this Court repeatedly

recognized that it is the original understanding of

the Sixth Amendment that controls its meaning, not

some abstract functional analysis. In Apprendi, this

Court recognized that “the historical foundation for

our recognition of [the rights in the Sixth Amendment] extends down centuries into the common law,”

530 U.S. at 477, and it is thus appropriate to look to

the common law as it existed at the Framing to determine how the Sixth Amendment’s guarantee

15

should apply in the context of sentencing, see id. at

478-83.

And as this Court explained in Giles v. California, 554 U.S. 353 (2008), when addressing the scope

of the Confrontation Clause, courts are not supposed

to “extrapolate from the words of the Sixth

Amendment to the values behind it, and then to enforce its guarantees only to the extent they serve (in

the courts’ views) those underlying values,” because

“[t]he Sixth Amendment seeks fairness indeed—but

seeks it through very specific means . . . that were

the trial rights of Englishmen.” Id. at 375; see Crawford v. Washington, 541 U.S. 36, 43-50 (2004) (looking to “historical background,” including the common law and early state practices, to determine the

meaning of the Confrontation Clause). 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.

In light of these more recent decisions and the

Sixth Amendment’s history, it was plainly wrong for

the Williams Court to conclude that a criminal jury

need not consist of twelve members. And since this

Court overruled Apodaca, Williams stands alone in

its rejection of the relevance of Sixth Amendment

history. But even if this Court’s decision in Williams

to engage in a functionalist analysis were correct,

that decision should still be overruled because, as

the next Section discusses, empirical research belies

the conclusion that juries of fewer than twelve persons are functionally equivalent to twelve-person juries.

16

III. Empirical Research Demonstrates that

Juries of Fewer than Twelve People

Undermine the Right to a Fair Trial

Guaranteed by the Sixth Amendment.

Even if this Court were to adopt Williams’s functionalist approach, it should still conclude that

twelve-person juries are constitutionally insufficient. Williams assessed the effect of jury size along

three main dimensions: first, the quality of jury deliberations; second, the ability of the jury to properly

represent a cross-section of the community; and

third, the reliability of jury verdicts. 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 52; see Zeisel, supra, at 714-15. Even at

the time, those “experiments” did not support the

conclusions the Williams Court drew, and since

then, empirical studies have confirmed that smaller

juries are worse in every regard Williams identified

as being essential to the Sixth Amendment’s fair

trial right, see Su & Goravara, supra, at 1014 (collecting empirical research demonstrating that sixmember juries are not the functional equivalent of

twelve-member ones).

A. Thoroughness of Deliberations

Williams was not altogether clear about what

factors it understood help to “promote group deliberation,” 399 U.S. at 100, but it suggested that the

ability of a dissenting juror to withstand the pressure to conform to the majority’s view was important, id. at 101 n.49. Williams reasoned that the

“operative factor” influencing dissenting jurors’ propensity to conform to majority pressure during

17

deliberations is the “proportional size of the majority

aligned against them,” id., meaning 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 every study Williams cited in support of this

proposition “found exactly the opposite.” Id. Each

study showed that if a dissenter has just one attitudinal ally, the dissenter is far more likely to resist

pressures to conform, regardless of the proportional

size of the majority against them. Id. Because

twelve-person juries are more likely to have multiple

dissenting members, see Zeisel, supra, at 722,

twelve-person juries improve dissenters’ ability to

resist majority pressure, leading to more considered

jury deliberations.

Research conducted since then confirms that

twelve-person juries are more deliberative in other

ways as well: they more accurately discuss facts in

deliberation, they rely on more probative information, they better recall such information, and

they deliberate longer. Smith & Saks, supra, at 465.

In one study of seventy-three mock criminal juries,

researchers found that the twelve-person juries discussed trial testimony more accurately than their

six-person counterparts. 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 from 2002 found twelve-person juries

relied less on non-probative and evaluative statements than six-person juries. Horowitz & Bordens,

supra, at 125-28. These findings are consistent with

group psychology literature explaining that larger

groups perform better because they can marshal

more resources than smaller groups. Saks & Marti,

18

supra, at 458; see 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.”).

Studies also indicate that larger juries deliberate

longer than smaller ones. Eleven studies examined

in a meta-analysis compared length of deliberations

between large and small juries, and all found larger

juries deliberated longer. Saks & Marti, supra, 45758. “The mean time difference for studies of actual

juries . . . is forty-four minutes.” Smith & Saks, supra, at 465. Longer deliberation time suggests “the

sharing of more facts, more ideas, and more challenges to the tentative conclusions of others.” Saks

& Marti, supra, at 458.

B. Representativeness of the Community

While Williams recognized that an “essential feature of the 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; cf. 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))),

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.

But Williams’s assumptions on this point 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

19

“populations of any given stratification.” Smith &

Saks, supra, at 458. To illustrate, in randomly impaneled six- and twelve-person juries from a population that is 10% minority, over half the six-person

juries will contain no minority members, while fewer

than a third of the twelve-person juries will lack minority representation. Zeisel, supra, at 716.

Empirical studies confirm that smaller juries exclude minorities much more often than twelve-person ones. A 1997 meta-analysis of all studies published over nearly two decades that assessed the empirical differences between six- and twelve-person

juries found overwhelming support for the proposition that twelve-person juries are significantly more

representative than six-person ones. Saks & Marti,

supra, at 457. The report analyzed seventeen studies involving over 2,000 juries. Id. at 452. Assessing

the aggregate results across the five studies that focused on minority representation, the authors concluded that the “effect of reduced jury size on minority representation is equivalent to a decrease in the

opportunity of 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 confirmed these earlier findings. The researchers in that study collected data

from 277 trials conducted between 2001 and 2007;

eighty-nine trials used six-person juries, and 188

used twelve-person juries. Shari S. Diamond et al.,

supra, at 434-35. Even though potential Black jurors comprised 25% of the venire before and after

peremptory challenges, 28% of the six-person juries

lacked even a single Black juror compared to only 2%

of the twelve-person ones. Moreover, 41% of six-person juries contained at least two Black jurors as compared to over 80% of twelve-person ones. Id. at 443.

20

This is important because, as a separate study

found, Black jurors are “vastly overrepresented” as

dissenting jurors urging acquittal. Thomas Ward

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

1593, 1599 (2018). Relatedly, a study examining felony trials in two Florida counties found that allwhite jury pools convicted Black defendants significantly more often—by 16 percentage points—than

white defendants. Shamena Anwar et al., The Impact of Jury Race in Criminal Trials, 127 Q.J. Econ.

1017, 1034-35 (2012). When there was at least one

Black juror in the jury pool, “the entire gap is eliminated.” Id. at 1035. And these results are particularly significant when combined with the studies discussed above that show that a dissenter’s propensity

to conform to majority pressures significantly decreases in the presence of at least one attitudinal

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

Another study focused on the representation of

Hispanic jurors found that 66% of six-person juries

had no Hispanic jurors compared to only 40% of

twelve-person juries. Diamond et al., supra, at 444.

Similarly, only 9% of six-person juries included at

least two Hispanic jurors compared to 25% of twelveperson juries. Id. The researchers emphasized that

such underrepresentation “would emerge for any minority,” not just racial or ethnic ones. Id. at 445.

C. Reliability of Verdicts

Williams claimed that “[w]hat few experiments

have occurred . . . indicate that there is no discernible difference between the results reached by the two

different-sized juries.” 399 U.S. at 78. But once

again, that proposition was completely wrong.

As an initial matter, “not one of [the] ‘experiments’” Williams cited “provide any evidence on the

21

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

(one source reported judges, clerks, and attorneys’

perceptions as to jury reliability, while another

simply stated that a test on this question was

planned for the future).

And Williams’s claim was not only unsupported,

it was also demonstrably wrong at the time and has

only been further contradicted by studies conducted

in the years since. Researchers assess the reliability

of jury deliberations by analyzing the relationship

between jury size and variance from an average verdict. This methodology is premised on the notion

that “the jury is a substitute for the full community,”

meaning that “the most correct verdict that could be

obtained would be one rendered by the full community.” Saks & Marti, supra, at 461. Thus, juries that

more consistently reach verdicts close to that which

the full community would reach are considered more

reliable.

Basic statistical principles explain that smaller

groups are more likely to reach outlier verdicts and

less likely to converge around the average outcome

the community would have reached. Zeisel, supra,

at 717. Empirical studies show the same thing. In

a 2002 study, researchers found that twelve-person

juries’ damage awards varied less than six-person

juries’ awards. See Horowitz & Bordens, supra, at

126. And another study involving mock criminal juries indicated that larger juries may be more sensitive to factual ambiguities than smaller ones. See

Angelo Valenti & Leslie Downing, Six Versus Twelve

Member Juries: An Experimental Test of the Supreme Court Assumption of Functional Equivalence,

1 Personality & Soc. Psych Bull. 273, 274 (1974).

***

22

In sum, the central premises underlying the Williams decision have all been undermined by more recent legal and factual developments. This Court

should grant review to protect the “sacred bulwark”

of the jury and restore coherence to its Sixth Amendment jurisprudence.

CONCLUSION

For the foregoing reasons, this Court should

grant the petition for a writ of certiorari.

Respectfully submitted,

ELIZABETH B. WYDRA

BRIANNE J. GOROD*

ANA M. BUILES

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 25, 2025

*Counsel of Record