The Unanimous Verdict
Introduction
A criminal trial can only result in a verdict once a jury has agreed. That principle seems obvious, but for much of our nation's history unanimity was not an unquestionable constitutional requirement in every state. The Supreme Court has settled the issue in Ramos v. Louisiana (2020) and ruled that the Sixth Amendment requires a unanimous jury verdict to convict a defendant of a serious offense.¹
The importance of that rule is now visible in Massachusetts as the jury in the closely watched trial of Lindsay Clancy reported to the court on September 1 that it was unable to reach a unanimous decision after four days of deliberation. The judge instructed the jurors to continue deliberating, leaving open the possibility of a verdict—or, if the deadlock continues, a mistrial.²
The case presents an unusual illustration of a constitutional principle: What happens when twelve jurors cannot agree and why does the Constitution require that they do?
Why unanimity?
The Sixth Amendment guarantees criminal defendants the right to trial by an impartial jury.³ The Supreme Court has interpreted that guarantee to include unanimity.
In Ramos v. Louisiana, the Court held that a state cannot convict a defendant of a serious offense on a non-unanimous verdict.¹ The decision relied partly on the historical understanding of the jury at the time of the Constitution's founding and partly on the Court's longstanding recognition that unanimity is fundamental to the jury trial right.
The decision overturned Apodaca v. Oregon (1972) which allowed certain state criminal convictions to rest on non-unanimous verdicts.¹ The constitutional rule is therefore demanding. If even one juror remains unconvinced that the prosecution has proved guilt beyond a reasonable doubt, the jury cannot return a guilty verdict. That does not necessarily mean the defendant has been proven innocent.
It means the government has failed to obtain the level of agreement the Constitution requires for conviction.
The history of non-unanimous juries
The history makes the rule more complicated. At the time Ramos was decided Louisiana and Oregon were the only states that still permitted non-unanimous jury verdicts for serious crimes.¹ Louisiana's system had roots in its 1898 constitutional convention which adopted the rule amid broader efforts to limit Black political participation and representation.⁴
The Supreme Court's decision in Ramos therefore did more than resolve a technical disagreement about jury procedure. It eliminated one of the final remnants of a system in which a person could be convicted despite significant disagreement within the jury.
The Court emphasized that unanimity has deep roots in Anglo-American jury practice.¹ The principle is not that every juror must agree because agreement is always easy or because juries are incapable of mistakes.
It is that the government should not obtain a criminal conviction when a required member of the defendant's community remains unconvinced.
The Clancy Jury
The Lindsay Clancy case provides a vivid example of what that principle looks like in practice. Clancy's Massachusetts trial lasted nearly six weeks and included more than 80 witnesses and more than 300 exhibits. The defense and prosecution have presented sharply different interpretations of her mental state and criminal responsibility.²
After beginning deliberations Thursday, the jury spent several days reviewing the evidence. On September 1, jurors informed Judge William Sullivan that they were deadlocked and could not reach a unanimous decision. The judge nevertheless directed them to continue deliberating.²
The judge's response is important as a deadlock does not automatically end a criminal trial. Massachusetts Rule of Criminal Procedure 27 provides that criminal verdicts must be unanimous and permits a judge to declare a mistrial when a jury cannot agree.⁵
The law therefore does not demand that jurors reach agreement at any cost.I t demands that a conviction cannot occur without agreement.
What a hung jury means
If a jury remains permanently divided the result is generally called a hung jury. A hung jury is not an acquittal but it is also not a conviction. The legal system instead recognizes that the prosecution has not obtained a verdict.
The Supreme Court addressed the consequences of deadlocked juries more than two centuries ago in United States v. Perez (1824). The Court held that when a jury cannot agree, a mistrial can constitute "manifest necessity" allowing the government to retry the defendant without violating the Double Jeopardy Clause.⁶
That rule creates an unusual constitutional result. A defendant can go through an entire trial, have a jury hear all the evidence and still face another trial because the first jury could not reach the required level of agreement.
The state gets another opportunity, not because the first jury found the defendant guilty, but because it never reached a final verdict.
The case for unanimity
The strongest argument for unanimity is that it gives each juror meaningful power. Suppose eleven jurors conclude that the evidence proves guilt while one juror believes the government's case leaves a reasonable doubt. Under a non-unanimous system, the eleven could potentially convict despite that disagreement.
Under the constitutional rule they cannot. The dissenting juror therefore cannot simply be treated as an obstacle to efficiency. That juror represents the possibility that something in the government's case has not been adequately established.
Unanimity also encourages deliberation. Jurors must explain their reasoning, respond to objections and attempt to persuade one another. The goal is not merely to count votes. It is to reach a collective judgment.
The case against unanimity
There is also a serious argument against requiring unanimity. Trials are imperfect. Jurors can disagree for reasons unrelated to the strength of the evidence. A single unreasonable holdout can prevent a verdict even after eleven jurors believe the prosecution has proved its case.
That can impose enormous financial and emotional costs on everyone involved. Victims and witnesses may have to participate again. Prosecutors must spend additional resources. Defendants may remain in legal uncertainty for months or years. A unanimity requirement can therefore produce inefficiency. But the constitutional system has essentially chosen to accept that cost.It prioritizes the danger of an unjust conviction over the convenience of obtaining a verdict.
The reasonable doubt connection
Unanimity cannot be separated from the beyond-a-reasonable-doubt standard. The prosecution carries the burden of proof.⁷ Jurors are not required to determine whether they think a defendant is probably guilty. They must decide whether the evidence satisfies a much higher standard.
Unanimity then adds another safeguard. The government must prove its case to a sufficiently high standard, and every juror must agree that it has done so. That combination creates a deliberately difficult path to conviction. The Constitution does not make conviction impossible, but makes the government earn it.
Why it matters
The Unanimous Verdict matters because it reveals that the jury is more than a democratic voting mechanism. Each juror has the power to prevent a conviction when the government's evidence has not persuaded them beyond a reasonable doubt.
That power can create frustration, delay and uncertainty. The Clancy case demonstrates exactly that. After days of deliberation, twelve jurors have not yet reached the agreement Massachusetts law requires.²
But the deadlock is not necessarily evidence that the jury has failed. It may demonstrate that the constitutional safeguard is functioning as designed.
The purpose of unanimity is not to guarantee quick decisions but to ensure that a criminal conviction represents the considered judgment of the entire jury rather than simply the preference of its majority.
Conclusion
The American jury system contains a remarkable rule: in a serious criminal case one juror can stand between the government and a conviction.
Ramos v. Louisiana made that principle constitutionally unavoidable.¹ Massachusetts law follows the same requirement, meaning that the Clancy jury cannot convict unless all twelve jurors agree.² ⁵
If the jury eventually reaches a verdict, unanimity will make that verdict more than a numerical majority. If it does not, the resulting deadlock will demonstrate the other side of the rule: sometimes the constitutional requirement of consensus means there can be no verdict at all. That is not necessarily a defect.
In American criminal law, twelve votes are not twelve preferences. They are twelve individual judgments that the government has proved its case.
Ramos v. Louisiana, 590 U.S. 83, 92–100 (2020). The Supreme Court held that the Sixth Amendment requires unanimous jury verdicts in serious criminal cases and that the requirement applies to the states through the Fourteenth Amendment.
Reuters, Jury in Lindsay Clancy's Murder Trial Says It Is Unable to Reach Unanimous Verdict (Sept. 1, 2026). The jury reported a deadlock after four days of deliberation, and Judge William Sullivan instructed the jurors to continue deliberating.
U.S. CONST. amend. VI.
See Ramos, 590 U.S. at 94–96, discussing the history and discriminatory origins of non-unanimous jury rules in Louisiana.
Mass. R. Crim. P. 27(a)–(b). Massachusetts requires a unanimous verdict and permits a mistrial when a jury cannot agree.
United States v. Perez, 22 U.S. (9 Wheat.) 579, 580 (1824).
In re Winship, 397 U.S. 358, 364 (1970), holding that due process requires the prosecution to prove every element of a criminal offense beyond a reasonable doubt.
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