The case is Ramos v. Louisiana, which the Court just this morning agreed to hear.
Here's the basic issue: In Apodaca v. Oregon (1972), the Supreme Court held that the Sixth Amendment requires unanimity for a verdict — but that the Fourteenth Amendment does not carry this rule over to the states, and that even 9–3 verdicts are constitutionally permissible. The Jury Trial Clause is thus the one Bill of Rights clause that is neither completely incorporated against the states via the Fourteenth Amendment, nor completely not incorporated. (Recall that the Bill of Rights originally applied only to the federal government, and has been applied to the states only through the Fourteenth Amendment.)
This partial incorporation is inconsistent both with prior Supreme Court practice and with McDonald v. City of Chicago (2010), the case that fully incorporated the Second Amendment. (McDonald calls an Apodaca-like approach "watered-down" incorporation.) In fact, in Apodaca, only one Justice — Justice Powell — concluded that the Jury Trial Clause required unanimity in federal trials but that this provision shouldn't be incorporated against the states. The other eight would have applied the Jury Trial Clause the same way both to federal and state trials, but four said (incorrectly, in my view) that it didn't require unanimity in either and four said it required unanimity in both. Justice Powell was the controlling vote, and that's how the partial incorporation result was reached.
Back in 2012, I filed a petition with the Court in a case raising the very same issue, Herrera v. Oregon; the Court denied then, and on some occasions since then, but I'm delighted that it has agreed to hear the matter now (whether because there are two new Justices on the Court, or for some other reason). Here's the argument in favor of the historical understanding that the Jury Trial Cause has indeed been understood as envisioning unanimous juries:
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The right to a unanimous jury verdict was firmly established when the Bill of Rights was framed. Sir William Blackstone noted it as an essential feature of the right to trial by jury:
[T]he trial by jury ever has been, and I trust ever will be, looked upon as the glory of the English law…. [I]t is the most transcendent privilege which any subject can enjoy, or wish for, 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. A constitution, that I may venture to affirm has, under providence, secured the just liberties of this nation for a long succession of ages.
2 Blackstone, Commentaries *378–79. Likewise, Blackstone listed the requirement of "unanimous suffrage" on a jury as part of the protection provided by the jury trial to "the liberties of England," and argued that "inroads upon this sacred bulwark of the nation [the jury trial] are fundamentally opposite to the spirit of our constitution." 4 id. *349–50. John Adams took the same view in America, writing that "it is the unanimity of the jury that preserves the rights of mankind." 1 John Adams, A Defence of the Constitutions of Government of the United States 376 (Philadelphia, William Cobbett 1797).
While the Bill of Rights was being ratified, Justice James Wilson — "who was instrumental in framing the Constitution and who served as one of the original Members of this Court," Victor v. Nebraska, 511 U.S. 1, 10 (1994) — stressed the unanimity requirement in his 1790–91 lectures: "To 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 (Philadelphia, Lorenzo Press 1804); see also 2 id. at 306, 311, 342, 351, 360 (further noting the unanimity requirement).
Justice Wilson's lectures were about law generally, not constitutional law as such. But he was discussing the meaning of "the trial by jury" in criminal cases. E.g., 2 id. at 344, 348. And it is the "right to a … trial, by an impartial jury" that the Sixth Amendment enshrines as a constitutional command (and that Article III, § 2, cl. 3, "The Trial of all Crimes, except in Cases of Impeachment, shall be by Jury," likewise enshrines). As George Hay, the United States Attorney in the Aaron Burr trial, put it, "The trial by jury is a technical phrase of the common law. By its insertion in the constitution, that part of the common law which prescribes the number, the unanimity of the jury and the right of challenge is adopted." United States v. Burr, 25 F. Cas. 55, 141 (C.C.D. Va. 1807).
St. George Tucker, author of the 1803 edition of Blackstone's Commentaries, likewise treated the Sixth Amendment as embodying the trial by jury described by Blackstone: His footnote on the Blackstone pages cited above (4 Blackstone *349–50, in 5 St. George Tucker, Blackstone's Commentaries 348–51 (Philadelphia, William Y. Birch & Abraham Small 1803)) noted that "the trial by jury" described in Blackstone's text was adopted in America, and secured by the Sixth Amendment. 5 Tucker, supra, at 348–49 n.2. Tucker cited the Sixth Amendment alongside its Virginia analog, which required "a speedy trial by an impartial jury of his vicinage without whose unanimous consent [the defendant] cannot be found guilty." Ibid. And he wrote that "without [the jurors'] unanimous verdict, or consent, no person can be condemned of any crime." 1 id. at App. 34.
Justice Joseph Story, in his great constitutional law treatise, likewise stressed that the constitutional "trial by jury" is the same "great privilege" that had been "part of that admirable common law." 3 Joseph Story, Commentaries on the Constitution of the United States § 1773, at 652 (Boston, Hilliard, Gray 1833). Justice Story endorsed the Blackstone articulation of the terms of that "great privilege": "I commend to the diligent perusal of every scholar, and every legislator, the noble eulogium of Mr. Justice Blackstone on the trial by jury." 3 id. at 654 n.1 (citing "3 Black. Comm. 379, 380, 381; 4 Black. Comm. 349, 350," which note the requirement of unanimity); see also 3 id. at 652 n.1 (citing "4 Black. Comm. 349"); 3 id. at 653 n.2 (citing "4 Black. Comm[.] 349, 350"). And in a different passage, Justice Story further confirmed that unanimity was understood as a constitutional requirement: His discussion of the constitutional standard for impeachment contrasted the two-thirds requirement for conviction in an impeachment trial with the rule in criminal trials, where "unanimity in the verdict of the jury is indispensable." 2 id. § 777, at 248.
Nathan Dane's influential 1823 General Abridgment and Digest of American Law similarly treated the Bill of Rights as providing that "the jury in criminal matters must be unanimous." 6 Nathan Dane, General Abridgment and Digest of American Law 226 (Boston, Cummings, Hilliard & Co. 1823). Another volume of the same work echoes this: "The value and excellency of [the criminal trial by jury] is fully declared in all our constitutions, and repeatedly in our laws. In virtue of it … the truth of every accusation must be established by the unanimous verdict of twelve [jurors] indifferently chosen." 7 id. 335. A Westlaw query for "dane abr!" "dane's abr!" & date(< 1/1/1900) reveals that in the 1800s the Abridgment was cited by this Court 38 times, and over 950 times by all the cases in the ALLCASES-OLD database.
Unanimity was also part of James Madison's understanding of the right to trial by jury. Madison's original draft of what would become the Sixth Amendment provided for trial "by an impartial jury of freeholders of the vicinage, with the requisite of unanimity for conviction, of the right of challenge, and other accustomed requisites," 1 Annals of Cong. 452 (1789).
The proposal was ultimately revised, with the "unanimity" language omitted, and there can be two alternative inferences from this change. One is "that Congress eliminated references to unanimity and to the other 'accustomed requisites' of the jury because those requisites were thought already to be implicit in the very concept of jury." Apodaca, 406 U.S. at 409–10 (plurality opinion). The other, which the Apodaca plurality endorsed, "is that the deletion was intended to have some substantive effect." Id. at 410.
But the plurality was mistaken; the historical evidence cited above shows that the unanimity requirement was indeed seen as "implicit in the very concept" of the Anglo-American criminal jury. Protecting the "trial by jury" safeguarded the essential incidents of the trial, such as the unanimity requirement, with no need for a detailed enumeration.
To be sure, the Jury Trial Clause did not constitutionalize all details of the common-law jury. As one early decision explained, "None would contend, at this day, in a trial of a writ of right, for the extraordinary [common-law] jury, called the grand assize, composed of four knights, 'girt with swords,' and who chose twelve other persons to be joined with them." Dowling v. State, 13 Miss. 664, 681–82 (1846) (holding that departures from common-law jury selection procedures may be constitutionally permissible under the Mississippi Constitution's jury trial provision). One could argue that even the choice of twelve as the number of jurors might be sufficiently arbitrary and accidental that some variation would be permitted, see Williams v. Florida, 399 U.S.86, 90 (1970), though petitioner takes no position on that question.
But, as Dowling put it, though "[t]he old common law has been insensibly changed and tempered to our situation and institutions," "the constitution must be construed to have adopted the generous privilege of the common law trial by jury in its essential elements." 13 Miss. at 682. Only those features that were "an accidental and not an absolute part of that institution, the mere superfluous forms and complicated proceedings of the English courts" are outside the constitutional guarantee. Ibid.
The unanimity requirement was indeed not just an "accidental," "superfluous" detail, but an "essential element[]" of the jury trial. It was a part of "our [English] constitution" that protected "the liberties of England" (Blackstone), and that was then accepted in America (as Story stressed). It "preserve[d] the rights of mankind" (Adams). It was "of indispensable necessity" (Wilson), "indispensable" to a criminal jury verdict (Story), part of the American design of "the several powers of government" (Tucker), and part of the trial by jury secured by "all our constitutions" (Dane).
And this view shared by these authorities is no accident, because there is nothing peripheral or arbitrary about the difference between a unanimous finding of guilt beyond a reasonable doubt and a finding of guilt entered over some jurors' dissent. As Justice Wilson put it, "To the conviction of a crime, the undoubting and the unanimoussentiment of the twelve jurors is of indispensable necessity," 2 Wilson, supra, at 350 (emphasis added). A nonunanimous jury conviction by definition means that some juror — in petitioners' case, two jurors — found that there was a reasonable doubt about the verdict.
Likewise, Justice Wilson wrote that "it would be difficult to suggest, for [the defendant's] security, any provision more efficacious than one, that nothing shall be suffered to operate against him without the unanimous consent of the delegated body." 2 id. at 316. The unanimity requirement is distinctive in this respect, because it is the best protection of its kind for the defendant. The twelve-member jury size, for instance, cannot be defended this way; one can always suggest a slightly larger jury as a theoretical protection for the defendant, yet the jury size has to be limited, so some arbitrary line must be drawn. But unanimity is both a feasible protection for defendants, and the most "efficacious" one for their "security."
[Footnote: The nonunanimous jury requirement is on balance less "efficacious" for the "security" of defendants, even though it allows 11-1 or 10-2 acquittals as well as 11-1 or 10-2 convictions. First, such splits in favor of acquittal are much rarer than such splits in favor of conviction. See, e.g., Calif. Admin. Office of the Courts, Final Report of the Blue Ribbon Commission on Jury System Improvement 72 (1996), http://www.courtinfo.ca.gov/?reference/?documents/BlueRibbonFullReport.pdf (reporting, based on Los Angeles County data, that 31% of all hung juries were 11-1 or 10-2 for conviction, and only 11% were 11-1 or 10-2 for acquittal). Second, even under a unanimity rule, prosecutors would be much more likely to retry a case after a 11-1 or 10-2 jury split for conviction than after a similar split for acquittal. Making such a split in favor of acquitting into a legal acquittal would thus help defendants little — but making a similar split in favor of conviction into a legal conviction would disadvantage defendants more. [UPDATE: Stupid error in this footnote ("less likely" instead of "more likely") corrected in the post.]]
Similarly, Justice Wilson noted that jurors, who represent the same society whose officials are prosecuting the defendant, may tend to sympathize with the prosecution. In a criminal prosecution, "on one side [is] an individual — on the other, all the members of the society except himself — on one side, those who are to try — on the other, he who is to be tried." 2 id. at 315. This means that "the representatives [i.e., the jurors] are not indifferent, and, consequently, may not be impartial." Ibid.
Because of this, Justice Wilson explained, "the evidence, upon which a citizen is condemned, should be such as would govern the judgment of the whole society," ibid., which is to say evidence that all reasonable members of society should accept as dispositive. To provide some assurance of this, "we may require the unanimous suffrage of the deputed body [i.e., the jury] who try, as the necessary and proper evidence of that judgment." Ibid.
This reasoning cannot be applied directly to jury size, where ten or fourteen might work as a proxy for society's views about as well as twelve would. It cannot be applied to some other historical features of the jury. But the reasoning fully supports Justice Wilson's conclusion that there is no substitute for unanimity in determining whether the evidence is "such as would govern the judgment" of all reasonable members of society. Whenever a presumptively reasonable juror finds a reasonable doubt, there is a basis to think that "the judgment of the whole society" may not support conviction — many other reasonable members of society might share the minority juror's doubts.
Justice Wilson's arguments supporting the unanimity requirement are powerful. And the value of the unanimity requirement in ensuring the protection of minority groups, promoting deliberation among jurors, and making convictions more credible to the public further supports Justice Wilson's thinking. "Studies suggest that where unanimity is required, jurors evaluate evidence more thoroughly, spend more time deliberating and take more ballots. In contrast, where unanimity is not required juries tend to end deliberations once the minimum number for a quorum is reached." American Bar Ass'n, Principles for Juries and Jury Trials, with Commentary principle 4.B, at 24 (2005), http://www.abanet.org/?jury/?pdf/final%20commentary_july_1205.pdf. [Footnote: See, e.g., Dennis J. Devine et al., Jury Decision Making: 45 Years of Empirical Research on Deliberating Groups, 7 Psychol. Pub. Pol'y & L. 622, 669 (2001) (discussing data that tends to show that the absence of a unanimity requirement leads to less deliberation); Kim Taylor-Thompson, Empty Votes in Jury Deliberations, 113 Harv. L. Rev. 1262, 1273 (2000) (same); id. at 1264, 1298–99 (noting that the absence of a unanimity requirement may lead to less consideration of the opinions of minority groups); Robert J. MacCoun & Tom R. Tyler, The Basis of Citizens' Perceptions of the Criminal Jury: Procedural Fairness, Accuracy, and Efficiency, 12 Law & Hum. Behav. 333, 337–38 & tbl.1 (1988) (noting that the public views unanimous juries as more accurate and fair).]
But whether the unanimity requirement is wise — or for that matter whether the jury trial requirement is wise — is not the main question here. The important point is that the unanimity requirement was understood to be a central, "indispensable" requirement of the right to trial by jury that the Framers knew and constitutionalized. Whatever flexibility the government may have in dispensing with historical features of the jury that are peripheral, accidental, or unimportant, such flexibility cannot extend to the essential requirement of unanimity.
[And as to why this unanimity requirement was accepted at the time the Fourteenth Amendment was written, and should thus be seen as incorporated against the states:]
The Fourteenth Amendment was said to secure (among other rights) the right to "trial by jury." Cong. Globe, 42d Cong., 1st Sess. app. 85 (1871) (statement of Rep. Bingham); Cong. Globe, 39th Cong., 1st Sess. 2765 (1866) (statement of Sen. Howard) ("right to be tried by an impartial jury of the vicinage"); Cong. Globe, 42d Cong., 2d Sess. 844 (1872) (statement of Sen. Sherman) ("right to be tried by an impartial jury"). And at the time the Fourteenth Amendment was ratified, "trial by jury" in criminal cases continued to be understood as requiring unanimity for conviction.
Michigan Supreme Court Justice Thomas Cooley, the "most famous" of the "late-19th-century legal scholar[s]" made this clear in his "massively popular" treatise. District of Columbia v. Heller, 128 S. Ct. 2783, 2811 (2008) (so labeling Justice Cooley and his treatise). "The jury must unanimously concur in the verdict." Thomas M. Cooley, A Treatise on the Constitutional Limitations Which Rest upon the Legislative Power of the States of the American Union 320 (Boston, Little, Brown & Co. 1868). And Justice Cooley joined Hill v. People, 16 Mich. 351, 358 (1868), which interpreted the Michigan Constitution's jury trial clause as implicitly guaranteeing a jury in which "unanimous agreement" is required for conviction.
Other leading commentators of that period took the same view: "[I]n a case in which the constitution guarantees a jury trial," a statute allowing "a verdict upon anything short of the unanimous consent of the twelve jurors" is "void." 1 Joel Prentiss Bishop, Commentaries on the Law of Criminal Procedure 532 (Boston, Little, Brown 1866). "That term ['jury'], when spoken of in connection with trial by jury in [the New York Constitution], imports a jury of twelve men whose verdict is to be unanimous. Such must be its acceptation to every one acquainted with the history of common law …." Theodore Sedgwick, Treatise on the Rules Which Govern the Interpretation and Application of Statutory and Constitutional Law 530 (New York, John S. Voorhies 1857).
"[T]he jury [must] be unanimous in rendering their verdict…. The principle once adopted has continued as an essential part of the jury trial …." John Norton Pomeroy, An Introduction to Municipal Law 78 (New York, D. Appleton & Co. 1864) (so stating even though the author disapproved of the unanimity requirement on policy grounds). "[A] trial by jury is understood to mean — generally — a trial by a jury of twelve men, impartially selected, and who must unanimously concur in the guilt of the accused before a legal conviction can be had." Joel Tiffany, A Treatise on Government, and Constitutional Law 366–67 (Albany, W.C. Little 1867). "[I]t is required that the jury shall be unanimous." John Proffatt, Treatise on Trial by Jury 119 (San Francisco, S. Whitney 1877). [Footnote: See Heller, 128 S. Ct. at 2789 (citing the Tiffany and Sedgwick treatises as authoritative); Blakely, 542 U.S. at 301–02 (likewise as to the Bishop treatise); Lewis v. United States, 518 U.S. 322, 334 (1996) (likewise as to the Proffatt treatise); Watt v. Alaska, 451 U.S. 259, 284 (1981) (likewise as to the Sedgwick treatise).]
These sources show that, when the Fourteenth Amendment was adopted, the right not to be convicted without a unanimous jury verdict was counted "among those fundamental rights necessary to our system of ordered liberty," McDonald, 130 S. Ct. at 3042 (plurality opinion), and as among the privileges or immunities of American citizenship, id. at 3088 (Thomas, J., concurring in the judgment).
