The movie 12 Angry Men is a hard one to forget. It’s often judged to be one of the great courtroom dramas of all time, even though the action isn’t in a courtroom. It takes place in a cramped, sweltering jury chamber. Eleven of the 12 jurors are determined to send a teenage boy to the electric chair for stabbing his father to death. Only Henry Fonda, in the role of a stubborn and idealistic architect who sees flaws in the evidence, believes in the boy’s innocence. One by one, he convinces all 11 of his opponents to see it his way, including a bitter, irrational and hot-tempered Juror No. 3, who bizarrely links the defendant to his own estranged son. After ranting angrily against Fonda, this juror breaks down in tears, changes his vote and the boy goes free.

Nearly everyone who watches this film comes away awed by the architect’s heroism, and also satisfied that the American jury system works as it was designed to. It may take time and some distasteful moments, but in the end justice wins out.

I’ve watched this movie more than once, and I react a little differently. I admire the architect’s courage and persistence, but I can’t help reflecting on the enormity of the task the legal process has forced on him. He can’t afford to lose a single vote. If Juror No. 3 had remained intransigent (which seems to me the more probable outcome in real life), the result would have been a hung jury, a new trial and very likely a conviction for murder. Does it really need to be unanimous? Is it possible that 10-2 or 11-1 might produce a larger number of fair results? I’m not saying it would; I’m just saying it’s not a totally crazy question.

As all of us know, the American legal system rarely asks this question. It is based virtually everywhere on the principle that no one should be convicted of a felony without a unanimous verdict. Only two states, Louisiana and Oregon, permit juries to render decisions with 10 or 11 votes out of 12.

By the end of this year, the number of renegade states will probably be down to one. In May, Louisiana state Sen. J.P. Morrell succeeded in winning legislative approval of a constitutional amendment that would ban 10-2 and 11-1 guilty verdicts and conform the state to the principle of unanimity. The voters seem likely to go along in November.

To say that the amendment has a broad range of elite support is to understate the case. The state’s major media are all on board, and The New York Times has weighed in. “Majority rule is good when it comes to the democratic process,” the Times editorialized recently, “but it’s not enough when someone’s constitutional rights and liberty are at stake.” Other prominent supporters of the change include not only the American Bar Association and liberal advocacy groups such as the American Civil Liberties Union but also the Koch brothers’ Americans for Prosperity and the Christian Family Forum at the other end of the ideological spectrum. The only organized opponents have been the state’s prosecuting attorneys.

To understand why this broad-based coalition exists, all you have to do is glance at the history of the Louisiana jury system. The state government and legal establishment approved the use of split verdicts in 1898 because they feared the impact of African-American jurors empowered by the 14th Amendment to the U.S. Constitution.

The establishment made no bones about this. Some years earlier, the New Orleans Times-Picayune had declared that newly emancipated black citizens were “wholly ignorant of the responsibilities of jurors, unable to discriminate between truth and falsehood in testimony, and capable only of being corrupted by bribes.” If one or two African-Americans ended up on a jury, it would be necessary to outvote them. So the legislature decided to permit guilty verdicts of 9-3, 10-2 or 11-1. In 1974, the law was changed to make 10 votes the threshold.

Critics of the existing law link it to the fact that Louisiana in recent years has had the highest incarceration rate in the United States. It’s been estimated that about 2,000 convicts are currently serving life sentences in Louisiana prisons on the basis of split verdicts.

Louisiana’s racist heritage is more than sufficient to explain its jury law. But what’s Oregon’s reason? That’s an interesting story, too. Oregon began allowing guilty verdicts with 10 votes in 1934, after a Jewish defendant named Jacob Silverman was acquitted of first-degree murder and ultimately served only three years for manslaughter because one lone juror held out for him. This sounds like a 12 Angry Men situation, but it was nothing like that. Silverman’s light sentence, in the wake of powerful circumstantial evidence against him, triggered a backlash toward Jews and immigrants and a statewide referendum that initiated split verdicts to dilute the influence of immigrant jurors.

The only current difference between the Louisiana and Oregon rules is that Oregon doesn’t permit split verdicts in murder cases. For all other felonies, it does. The Oregon law has been challenged in federal court numerous times, including last year in a petition to the Supreme Court, but without success. The court has declined to reconsider a 1972 ruling that split-verdict systems in state courts are constitutional.

But how serious a problem are split-verdict systems? The origins of such laws are offensive, but they aren’t in themselves sufficient to discredit the practice. Louisiana is still far from being a paragon of social justice, but African-Americans are eligible to serve on juries in reasonable proportion to their presence in the population and to insist on fair treatment when they get there. The real argument against split-verdict juries is that they tend to marginalize dissenters of all colors and creeds, because their votes are not needed when they are one or two against 10 or 11.

The Baton Rouge Advocate has done some excellent research on this point and taken powerful testimony. A juror in a kidnapping case said that “no one told me it was a 10-2 state. There was no attempt to change my mind. It was over and I was like, ‘I don’t know what just happened here.’”

The newspaper found that split verdicts were 30 percent more common in cases where the defendant was black. African-American jurors were more than twice as likely to be on the dissenting side of a split verdict as their white counterparts. For many critics of the system, these numbers alone suggest residual racism. Strictly speaking, however, they aren’t a smoking gun -- they don’t prove that split verdicts are in themselves a miscarriage of justice.

One reason it’s possible to question the sacred status of the unanimity requirement is that we are living in a time when notions of jury nullification are an unavoidable part of the legal system and the trial process. Nullification in American courts goes back to the 18th century, when the printer John Peter Zenger was acquitted in a landmark libel case because a jury found his published words to be true, even though the law expressly said truth was no defense. The jury found the law unjust.

In the centuries since then, millions of words have been written on the topic of when jurors are entitled to dispense with the law in the interest of what they consider to be higher justice. Many commentators have said this is permissible when the law or the trial is blatantly discriminatory. But what if a juror isn’t concerned with the facts of the case? What if she believes the entire legal system -- or the whole society -- is tainted by racism, sexism or a disregard for individual liberty? Does that mean she can refuse to consider the evidence and free a guilty defendant?

Some very smart lawyers think so. Paul Butler, a professor at Georgetown University Law School, has been making this case for more than two decades. “If [jurors] think that the police are treating African-Americans unfairly, by engaging in racial profiling or using excessive force,” Butler wrote a few years ago, “they don’t have to convict, even if they think the defendant is guilty.”

The arguments for nullification have become louder in the past few years amid the growing distrust of police tactics. Nullification T-shirts are easy to purchase online. Any controversial criminal trial is likely to generate at least a few protesters proudly wearing them.

Today’s nullifiers may be reviving a long-standing tradition in American jurisprudence. But just one of them on a jury can block a defendant’s conviction even in the face of the strongest evidence. Orin Kerr, a law professor at the University of Southern California, raised this issue eloquently in 2015. “The evidence can be overwhelming,” Kerr wrote, “and 11 of the jurors can believe fervently that a particular case is the most compelling prosecution ever brought. But a single juror, accountable to no one, can put the kibosh on the case based on his own vision of justice that may have no connection to anyone else’s. We don’t normally think of placing all the power in one unelected person who answers to no one as a democratically accountable approach.”

I don’t expect that state courts in this country will ever go back to 10-2, or 11-1. We have made a decision for mandatory unanimous verdicts (unlike England or Scotland, incidentally) and that decision has broad public support, even in Louisiana. I’m just suggesting that this issue, like virtually all issues in American jurisprudence, is a bit more complicated than it may seem at first.