Twelve Angry Men: The Origin of Twelve-Person Criminal Juries

Sara Kircher*

When most people think of a jury, they think of twelve randomly selected strangers deciding someone’s guilt or innocence in a criminal case.  But where did this idea of a twelve-person jury come from?  The United States Constitution guarantees a trial by an impartial jury, but says nothing about the number of people required.¹  Why, then, did twelve become the standard?

The short answer is that twelve was brought over from English common law.²  The Founders likely did not specify a number in the Constitution because it was already presumed.  There was no need to clarify something quite so obvious.³  When the question did come before the Supreme Court, the Court stated, “‘Trial by jury’…is a trial by a jury of 12 men….This proposition has been so generally admitted, and so seldom contested, that there has been little occasion for its distinct assertion.”⁴  In other words, because a twelve-member jury was so widely accepted, there was no need to explicitly state it anywhere.  The Court further confirmed this point in a later case when it stated a “constitutional jury” means twelve, and that when a jury is reduced to eleven, it ceases to be constitutional.⁵

Despite this history, the Supreme Court chose to reexamine the twelve-person jury in Williams v. Florida in 1970.⁶  In this case, Mr. Williams was charged with robbery, and in accordance with Florida law, a six-person jury was impaneled.⁷  Following his conviction, Mr. Williams appealed, claiming his Sixth Amendment rights had been violated by the failure to provide him with a twelve-person jury.⁸  The Court ultimately held that the Fourteenth Amendment guaranteed a trial by jury, but that twelve people were not necessary.⁹  It reasoned that number twelve was a “historical accident” unrelated to the purpose of a jury.¹⁰  The Justices further explained that because they could not determine the exact intent of the Framers, they could not say that a twelve-member jury was a required component of the Sixth Amendment.¹¹  Thus, the Court concluded Mr. Williams’s rights were not violated by a six-man jury, and his conviction was upheld.¹²

Just a few years later, the Court held that a trial by a jury of less than six people was unconstitutional.¹³  Mr. Ballew was charged with distributing obscene materials, and under the Georgia Constitution, was granted a jury of five people.¹⁴  The jury deliberated for only thirty-eight minutes before returning a guilty verdict.¹⁵  The Court explained that smaller juries are “less likely to foster effective group deliberation,” and as such, are more likely to incorrectly apply the laws to the facts.¹⁶  Furthermore, smaller groups are less likely to overcome individual biases to reach a just result.¹⁷  Smaller juries also contribute to a number of other issues such as decreased accuracy, diminishment in minority viewpoints in deliberations, and a reduction in minority group representation.¹⁸ The Court found that these risks outweighed the state’s interests in reducing financial costs and court time.¹⁹

Today, the Federal Rules of Criminal Procedure, state that a jury consists of twelve people, unless the rules provide otherwise.²⁰  The rules do further state that the parties can stipulate in writing to a jury of less than twelve.²¹  Otherwise, a verdict can only be returned by a jury of eleven if the court finds good cause to dismiss a juror early.²²  Though the federal rules do not lay out a bright line limit as to the number of jurors the parties may stipulate to, it seems unlikely this will become a significant issue in the future.  Justice is best served on both sides when there is a jury of twelve to meaningfully deliberate the issues.

* Sara Kircher, J.D. Candidate, University of St. Thomas School of Law Class of 2027 (Associate Editor).

1. U.S. Const. amend. VI. ↩︎
2. Wanling Su, Does a Jury Require 12 People? The Supreme Court Has a Chance to Correct the Record, Time (Dec. 17, 2025, at 14:38 CT), https://time.com/7340393/12-person-jury-supreme-court/ [https://perma.cc/RQ2B-M2HL]. ↩︎
3. Thompson v. Utah, 170 U.S. 343, 349 (1898) (stating that the jury referred to in the Constitution and the Sixth Amendment is “constituted, as it was at common law, of twelve persons, neither more nor less”). ↩︎
4. Cap. Traction Co. v. Hof, 174 U.S. 1, 13–14 (1899). ↩︎
5. Patton v. United States, 281 U.S. 276, 292 (1930). ↩︎
6. 399 U.S. 78 (1970). ↩︎
7. Id. at 79–80. ↩︎
8. Id. at 80. ↩︎
9. Id. at 86. ↩︎
10. Id. at 89–90. ↩︎
11. Id. at 98–100. ↩︎
12. Id. at 103. ↩︎
13. Ballew v. Georgia, 435 U.S. 223, 223 (1978). ↩︎
14. Id. at 225–226. ↩︎
15. Id. at 227. ↩︎
16. Id. at 232. ↩︎
17. Id. at 233. ↩︎
18. Id. at 134–237. ↩︎
19. Id. at 243. ↩︎
20. Fed. R. Crim. P. 23(b)(1). ↩︎
21. Fed. R. Crim. P. 23(b)(2)(A). ↩︎
22. Fed. R. Crim. P. 23(b)(2)(B), Fed. R. Crim P. 23(b)(3). ↩︎