Thurgood Marshall’s tenure on the Supreme Court coincided with a period of profound transformation in American criminal justice jurisprudence. From the tail end of the Warren Court through the Burger and into the Rehnquist Courts, the national debate over the rights of the accused, the fairness of capital punishment, and the scope of government power all took center stage. During this era, Marshall emerged as one of the most vocal and consistent defenders of constitutional protections for criminal defendants, shaping—and often vigorously contesting—major rulings that continue to reverberate in legal discourse today. Whether writing concurrences, majorities, or dissents, his opinions underscored a core belief that constitutional guarantees of due process and equal protection must be actively enforced to prevent the systemic injustices he had witnessed firsthand as a civil rights litigator.
This section explores several pivotal cases in which Justice Marshall’s influence was particularly visible, focusing on the landmark decisions that reshaped capital punishment jurisprudence and the due process rights of criminal defendants. We begin by examining Furman v. Georgia (1972), the seminal ruling that temporarily halted the death penalty in the United States, and then turn to Gregg v. Georgia (1976), the decision that reinstated capital punishment under revised state statutes. From there, we move into the broader landscape of Marshall’s opposition to the death penalty, before delving into a crucial case on prosecutorial disclosure obligations—United States v. Bagley (1985)—where Marshall joined a forceful dissent urging stringent safeguards to ensure fairness in criminal trials. Through these cases, Marshall’s commitment to robust constitutional protections becomes clear, illuminating the ways in which he sought to guard against both overt and subtle forms of injustice in American criminal law.
By the time Thurgood Marshall joined the Supreme Court in 1967, the Warren Court had already ushered in a “due process revolution.” Through decisions such as Mapp v. Ohio (1961), Gideon v. Wainwright (1963), and Miranda v. Arizona (1966), the Court expanded the procedural protections available to criminal defendants, ensuring that states as well as the federal government adhered to constitutional standards. Although Marshall was not on the bench for those landmark rulings, he enthusiastically supported their rationale and advocated for similar expansions where gaps remained.
However, as the Court transitioned from Chief Justice Earl Warren to Chief Justice Warren Burger in 1969, momentum shifted. Public anxieties about crime rates, coupled with the emergence of a more conservative judicial philosophy, led to rulings that began to constrain some of the Warren Court’s expansive readings of criminal defendants’ rights. Marshall’s presence thus became essential in preserving—or at least articulating in dissent—the broad conception of due process and equal protection championed in the 1960s. Time and again, he would challenge the Court’s narrowing of procedural safeguards, warning that chipping away at those protections would disproportionately harm the poor, racial minorities, and other marginalized communities.
Against this backdrop, one of the most consequential developments in American criminal justice was the Court’s examination of capital punishment’s constitutionality. By the early 1970s, the NAACP Legal Defense and Educational Fund—building on strategies reminiscent of Marshall’s earlier civil rights litigation—had assembled a body of evidence demonstrating that the death penalty was applied capriciously, often reflecting deep racial and socioeconomic biases. Thurgood Marshall was well-aware of these inequities, given his career-long exposure to systemic injustice in the legal system.
The Case and Its Holding
In Furman v. Georgia, the Court was presented with three consolidated cases in which individuals had been sentenced to death under state statutes that granted juries wide discretion in imposing capital punishment. The key question was whether these impositions violated the Eighth Amendment’s ban on cruel and unusual punishment. In a 5–4 decision, the Court held that the death penalty, as administered, was unconstitutional. Although the majority did not provide a single unifying opinion—each of the five justices wrote separately—the effect was monumental: it effectively suspended capital punishment across the country until states could devise more guided sentencing procedures that would eliminate arbitrary or discriminatory application.
Marshall’s Concurrence
Justice Marshall’s concurrence in Furman was groundbreaking in its breadth, insisting that the death penalty itself, not merely its method of imposition, violated constitutional principles. His reasoning rested on two pillars. First, he underscored the racially biased manner in which capital punishment had been imposed. Studies and anecdotal evidence showed that defendants from minority backgrounds were far more likely to receive death sentences, especially if the victim was white. Second, he argued that capital punishment contravened society’s evolving standards of decency. For Marshall, the Eighth Amendment demanded that punishment reflect a basic respect for human dignity, and he believed the death penalty inherently clashed with that principle.
Rather than focusing narrowly on how capital punishment was applied, Marshall proposed that if the American public truly understood the death penalty’s procedural and moral pitfalls, they would reject it entirely. In effect, he invited citizens to reflect on capital punishment’s compatibility with contemporary moral values—a call that has resonated in subsequent legal and ethical debates.
The reprieve from capital punishment ushered in by Furman was short-lived. In the years following the decision, numerous states revised their death penalty statutes, introducing mandatory sentencing guidelines or “bifurcated” trials designed to limit arbitrary discretion. One of these revised statutes came under review in Gregg v. Georgia (1976).
The Case and Its Holding
In Gregg, the defendant had been convicted of armed robbery and murder under a new Georgia statute that provided for a separate sentencing phase, required the jury to consider specified aggravating and mitigating circumstances, and allowed for automatic appellate review of any death sentence. By a 7–2 vote, the Court upheld this statute, concluding that it offered sufficient procedural checks to prevent the arbitrary imposition of the death penalty. Thus, capital punishment was reinstated, provided states adhered to similarly structured guidelines.
Marshall’s Dissent
Justice Marshall, joined by Justice William J. Brennan, Jr., dissented. His position in Gregg was consistent with his concurrence in Furman: the death penalty itself, under any protocol, contravened the Eighth Amendment. He argued that tinkering with procedures did not address the deeper moral and constitutional objections. Even if a statute seemed to minimize arbitrariness, there remained unquantifiable subjective elements—implicit biases, inconsistencies among prosecutors, and variations in defense counsel effectiveness—that could lead to discriminatory outcomes. Furthermore, Marshall reasserted that a punishment as irrevocable as death clashed with evolving standards of decency, risking irreversible error and perpetuating a cycle of state-sanctioned violence.
While the majority in Gregg believed they had found a workable compromise between the public’s demand for harsh punishment and the Constitution’s ban on cruel and unusual punishment, Marshall’s dissent was a forceful reminder that the moral debate persisted. In the years that followed, he remained steadfast, dissenting in virtually every death penalty case that came before the Court.
Over the two decades after Gregg, Marshall continued to articulate his unwavering opposition to the death penalty. In numerous decisions—ranging from McCleskey v. Kemp (1987), where he condemned the Court’s reluctance to confront racial disparities in capital sentencing, to Payne v. Tennessee (1991), which permitted victim-impact statements—he insisted that capital punishment was, at its core, fundamentally flawed.
Critics labeled him an absolutist on the issue, but Marshall viewed his stance as consistent with the original meaning of the Eighth Amendment when interpreted in the context of modern standards and a history of racial subjugation. He maintained that neither procedural reforms nor popular support could remedy what he saw as an inherent incompatibility between the death penalty and a constitutional promise of equal justice. Although he never persuaded the majority to adopt his view, his dissents have endured as potent moral critiques, often cited by abolitionists and legal scholars who continue to question the fairness and finality of capital punishment.
While capital punishment dominated the headlines, Marshall’s commitment to criminal defendants’ rights manifested in other areas as well. One of the most important dimensions of criminal procedure—a dimension that extends far beyond the question of life or death—concerns the disclosure of evidence by prosecutors. The Constitution demands that defendants have access to any exculpatory or impeaching information that the government possesses, a principle established in Brady v. Maryland (1963). Yet the precise contours of this obligation continued to be litigated for decades, with Marshall often calling for robust enforcement to prevent miscarriages of justice.
United States v. Bagley (1985): The Disclosure Quandary
An illustrative example emerged in United States v. Bagley, decided in 1985. This case posed a critical question: what standard should courts apply to determine whether prosecutors’ failure to disclose certain pieces of evidence—particularly evidence that could impeach the credibility of government witnesses—requires reversal of a conviction? The defendant, Bagley, had been charged with narcotics and firearms offenses. During trial, the prosecution did not disclose that two key government witnesses had signed contracts with the Bureau of Alcohol, Tobacco, and Firearms, providing them financial incentives contingent on successful convictions. Bagley argued that knowledge of these contracts would have allowed him to impeach the witnesses’ credibility, potentially altering the outcome of his trial.
The Plurality’s Holding
Writing for a plurality, Justice Blackmun concluded that the standard for determining materiality in cases of undisclosed impeachment evidence was the same as that applied for undisclosed exculpatory evidence under Brady: whether there was a “reasonable probability” that, had the evidence been disclosed, the result of the proceeding would have been different. This “reasonable probability” standard was intended to protect defendants while still granting courts some leeway in assessing whether the omission genuinely undermined confidence in the verdict.
Marshall Joins the Dissent
Although Blackmun wrote the plurality opinion, he also authored a separate dissent regarding certain procedural aspects of the case—specifically how lower courts should handle the remand. Marshall joined this dissent, emphasizing that prosecutorial nondisclosure of evidence bearing directly on witness credibility strikes at the heart of a fair trial. From Marshall’s perspective, if the government withheld information that a witness stood to gain from a defendant’s conviction, there should be little question that this omission could taint the proceeding. A bright-line rule, requiring automatic reversal or at least rigorous scrutiny whenever impeachment evidence was suppressed, might have been the best way to preserve the integrity of criminal trials.
Marshall’s Deeper Concerns
For Marshall, Bagley was not merely about parsing legal standards; it was about ensuring that the Constitution’s promise of due process was a reality, especially for defendants who lacked the resources to mount an independent investigation into prosecution witnesses. He had seen, time and again, how disparities in wealth and power could tilt the scales of justice. Without robust disclosure obligations, a defendant might never know that a key government witness was financially motivated to testify, or that the witness’s credibility was otherwise compromised. The risk of wrongful conviction, in Marshall’s view, was far too high to justify any compromise on prosecutorial transparency.
The significance of Bagley thus lies in its illustration of Marshall’s broader philosophy: the constitutional guarantee of a fair trial demands vigilant enforcement, particularly in situations that allow prosecutorial advantage to flourish. Although Marshall did not prevail in securing a more stringent bright-line rule, his position in Bagley resonates in ongoing debates about prosecutorial misconduct and discovery obligations, including the persistent calls for open-file discovery in criminal cases.
Marshall’s work in the criminal justice realm encapsulates many of the themes that defined his Supreme Court career. First and foremost, he believed that constitutional rights must be interpreted expansively to protect individuals against the immense power of the state. Where others might have deferred to legislative judgments or prosecutorial discretion, Marshall insisted that rigorous scrutiny was necessary to uncover and deter potential abuse.
Second, his views on capital punishment and fair trials underscored an unflagging commitment to human dignity and moral responsibility. Marshall’s stance on the death penalty—particularly in Furman and Gregg—revealed a conviction that no amount of procedural tinkering could salvage a punishment he saw as unavoidably cruel and unusual. In this sense, his dissents can be read as moral treatises as much as legal documents, warning future generations of the ethical pitfalls inherent in capital sentencing.
Third, Marshall’s participation in United States v. Bagley shows that his advocacy for fairness transcended questions of life or death. He recognized that every criminal proceeding carries high stakes for defendants, whose liberty, reputation, and future often depend on the fairness of the trial process. By stressing the importance of transparent prosecutorial conduct, Marshall aimed to correct systemic imbalances—recognizing that the prosecution ordinarily wields vastly greater investigative and bargaining power.
Finally, Marshall’s criminal justice opinions, particularly his dissents, have aged into something akin to guideposts for reformers. While the Court has not categorically abolished the death penalty, the broader societal conversation about racial bias, wrongful convictions, and the ethics of capital punishment has become more robust, often citing his warnings. Similarly, the push for stronger disclosure rules in criminal cases continues, with many prosecutors’ offices and state legislatures adopting or debating more expansive discovery obligations in line with Marshall’s vision of a fairer system.
In the pantheon of American legal history, Thurgood Marshall’s contributions to criminal justice stand among his most enduring legacies. He repeatedly warned that constitutional guarantees amount to hollow rhetoric if not enforced in practical, concrete terms. From his fervent opposition to the death penalty as a punishment incompatible with human dignity, to his insistence on stringent prosecutorial disclosure standards, Marshall’s jurisprudence reflects the fusion of moral conviction and legal craft that defined his career.
When one considers the wider context—Marshall’s own background in segregated courthouses, his relentless fight for civil rights, and his abiding belief that the Constitution should serve as a shield for the powerless—his positions on these cases become even more resonant. They are not mere abstractions in legal theory; they are the culmination of a lifetime of confronting injustice and demanding that the law live up to its highest aspirations.
Moreover, the enduring debates over capital punishment, police powers, mass incarceration, and prosecutorial ethics confirm that Marshall’s concerns were not fleeting historical footnotes but prescient commentaries on systemic vulnerabilities. Contemporary movements calling for criminal justice reform echo many of his insights, suggesting that his voice—often in dissent—continues to guide advocates seeking a more equitable legal system. Indeed, long after Furman, Gregg, and Bagley receded from the front pages, Marshall’s argument that fairness, dignity, and transparency must remain paramount in criminal proceedings stands as a clarion call for those who strive to reconcile justice with constitutional ideals.
By delving into these pivotal criminal justice cases, we gain not only a clearer understanding of Marshall’s legal acumen but also a deeper appreciation for his humanity. He recognized that what happens in a courtroom can mean the difference between freedom and captivity, life and death. Few places in American public life reveal the chasm between principle and practice as starkly as the criminal justice system. And few voices in Supreme Court history have so consistently and powerfully demanded that the United States close that chasm as did Thurgood Marshall.
In the pages that follow, we will extend our survey to other domains in which Marshall left his mark—areas such as civil rights, affirmative action, and the First Amendment. Yet his tenure’s lasting imprint on criminal justice, particularly in the realm of capital punishment and due process, stands among the most vivid illustrations of how he wielded the power of his office to champion constitutional guarantees. Through majority opinions, concurrences, and especially dissents, Marshall pressed the Court to confront the harsh realities faced by criminal defendants, remaining steadfast in his pursuit of a legal system that would embody the very equality and fairness he had spent his life advancing.