The Supreme Court (Jacquelyn Martin/AP)

David Cole teaches constitutional law, national security, and criminal justice at Georgetown University Law Center. He is also the legal affairs correspondent for The Nation, and a regular contributor to the New York Review of Books.

What makes a great Supreme Court dissent? Justice John Marshall Harlan’s lone dissent in Plessy v. Ferguson in 1896, proclaiming that the Constitution is “color-blind,” was vindicated 58 years later in Brown v. Board of Education, which declared segregated schools unconstitutional. Louis Brandeis’s 1928 dissent in Olmstead v. United States, declaring a “right to be let alone,” led the court, years later, to recognize privacy rights not only in the specific setting presented by that case — wiretapping — but also with respect to the rights to contraception and abortion. Modern First Amendment doctrine can be traced to a pair of dissents penned by Oliver Wendell Holmes Jr. and Brandeis in the early part of the 20th century. And Justice Harry Blackmun’s compelling articulation of privacy principles in refusing to join the Supreme Court’s upholding of a Georgia law making homosexual sex a crime became the law of the land 17 years later, when a majority of the court reversed Bowers v. Hardwick in Lawrence v. Texas.

Each of these historic opinions was eloquent, passionate, well-reasoned and persuasive — as any good dissent must be. A Supreme Court majority opinion has the force of law, regardless of how well it is written or reasoned. It reflects what Justice William Brennan called “the rule of five”: Whatever five justices agree to, by definition, becomes law. A dissent’s only influence, by contrast, depends on its ability to articulate a more appealing vision of what the law should be. Majority opinions are exercises in power; dissents are appeals to our better judgment. The majority prevails, but the dissenter’s role is by far the more romantic; it is the work of the individual who, on principle, stands against the crowd. While precedent demands that justices follow the law, we celebrate as great those who departed from precedent as lone dissenting voices and ultimately saw their views adopted into law. We assign authority to the majority, but we valorize the dissenter.

Except when we don’t. The annals of the Supreme Court are full of dissents, many of them eloquent and passionate and well-reasoned, that never attracted a majority of the court. They remain individual pleas, perhaps read by law students to enliven class discussion (thank you, Justice Scalia!) but exercising little influence over the course of the law. Brennan wrote one of the most moving dissents in the court’s history in McCleskey v. Kemp, a 1987 decision that upheld Georgia’s administration of the death penalty, despite evidence that, after controlling for 39 nonracial variables, a defendant who killed a white victim was 4.3 times more likely to get the death penalty than a defendant who killed a black victim. Yet Brennan’s dissent has not been transformed into constitutional doctrine and probably never will be.

Antonin Scalia has never been shy about expressing his disagreements, and his opinions are well-written and forceful (if often too forceful for his own good). But few of his dissents have become law. He harshly criticized, for example, the court’s decision to strike down Texas’s sodomy statute in Lawrence, warning that if the court’s reasoning were accepted, a right to same-sex marriage would be next. His prediction proved correct, but if he thought it would convince anyone to part company with the majority view, he was mistaken. He offered equally impassioned dissents in Planned Parenthood v. Casey, which reaffirmed Roe v. Wade’s recognition of a right to reproductive choice, and in both of the recent failed challenges to the Affordable Care Act. But there is little likelihood that these opinions will prevail in the long run.

Unless, of course, President Rubio appointed a justice sharing Scalia’s perspective to replace one of the current liberal justices. In that case, there would be a solid conservative majority, Justice Anthony Kennedy would lose his status as swing voter, and many of Scalia’s views would have five votes.

What determines a great dissent, in other words, is not necessarily the power of the argument but the shifting tides of history. The dismantling of de jure segregation had more to do with the civil rights movement than Harlan’s plea in Plessy, and the recognition of a right to same-sex marriage is more attributable to the work of gay rights organizations than to Blackmun’s dissent in Bowers v. Hardwick. History, not rhetoric or cogency, determines whether a dissent wins out in the long run. Yet by articulating a compelling alternative legal vision, a persuasive dissent can contribute to the arc of historical change.

So that makes it especially appropriate that Melvin Urofsky, one of the nation’s great legal historians, has taken up the subject. His new book, “Dissent and the Supreme Court,” masterfully recounts the history of dissent on the court, from its earliest days, when dissents were rare and strongly discouraged, to the modern era, when they often outnumber majority opinions. (Under Justice John Marshall, 93 percent of the court’s decisions were unanimous; by 1952, only 22 percent were.) The history of dissent, it turns out, is the history of constitutional law itself, because so often evolutions in constitutional doctrine are first voiced by lone dissenters.

The practice of dissent is, Urofsky’s account suggests, a sign of strength. The court preferred unanimous opinions in its early days because its authority was not yet established, and it sought to present a united front. Only as the court gained confidence (and as the country gained confidence in the court) did the number of dissents grow. As Justice William O. Douglas argued, that “judges do not agree . . . is a sign that they are dealing with problems on which society itself is divided. It is the democratic way to express dissident views.”

Urofsky concentrates on the dissents that have indeed prevailed over time. Hugo Black argued that every criminal defendant deserves a lawyer long before the court so ruled. Robert Jackson, Owen Roberts and Frank Murphy objected to the Supreme Court’s rubber-stamping of the internment of 110,000 Japanese and Japanese Americans in World War II; some 40 years later, Congress formally apologized and paid reparations. Douglas stood up to McCarthyism and dissented from the court’s decision upholding criminal convictions of Communist Party leaders. Holmes and Harlan dissented from decisions striking down progressive labor legislation in the early 20th century. They were all proved right by history.

These stories reflect what is best about the legal process. They illustrate that the views of a lone justice, if she is willing to part company with her peers and articulate her reasoning clearly and forcefully, can help change the course of history and the content of our highest law.

It is not possible, of course, to isolate the influence a dissent has from the many other factors that contribute to constitutional change. Were Holmes and Harlan’s dissents about the propriety of laws protecting workers proved right by the force of their reasoning, by the economic pressures of the Great Depression, by Franklin Roosevelt’s threat to “pack” the court or by all of the above? Urofsky understands that many factors contribute to constitutional change, but he demonstrates here that dissenting opinions are an important — and heroic — part of the picture.

However difficult it may be to measure the precise impact of dissent on the law, one thing is clear: The justices like it. Douglas said that “the right to dissent is the only thing that makes life tolerable for a judge on an appellate court.” And when John Paul Stevens was asked, “If you could fix one thing about the American judicial system, what would it be?,” he replied, “I would make all my dissents into majority opinions.”

Dissent and the Supreme Court
Its Role in the Court’s History and the Nation’s Constitutional Dialogue

By Melvin I. Urofsky

Pantheon.
528 pp. $35