Thurgood Marshall’s tenure on the Supreme Court coincided with—and contributed to—a transformative era in American criminal procedure. Arriving in the late 1960s, he inherited the Warren Court’s “due process revolution,” which expanded protections for defendants via landmark cases like Mapp v. Ohio (1961), Gideon v. Wainwright (1963), and Miranda v. Arizona (1966). Although Marshall did not participate in those earlier rulings, he deeply embraced their ethos: constitutional guarantees must be interpreted so as to protect individuals—especially the poor and marginalized—from the formidable powers of law enforcement. Over the next two decades, as the Court’s composition shifted under Chief Justices Warren Burger and William Rehnquist, Marshall would emerge as a consistent voice urging vigorous enforcement of Fourth, Fifth, Sixth, and Fourteenth Amendment rights.
While later Courts would grow more conservative, gradually tempering or complicating some of the Warren Court’s doctrines, Marshall’s opinions, both in majorities and frequent dissents, laid down markers for how far governmental authorities could go before trampling the rights of the accused. Through key decisions concerning search and seizure, the right to counsel, prosecutorial disclosure, and the fairness of criminal trials, Marshall’s reasoning continued to resonate long after his retirement in 1991. This chapter section explores the evolution of criminal procedure jurisprudence after Marshall’s era, focusing on how his foundational perspectives informed—or found friction with—subsequent Supreme Court rulings. In doing so, it highlights the enduring influence of Marshall’s call for robust procedural safeguards, even as the Court’s center of gravity shifted toward granting police and prosecutors greater latitude.
Wariness of State Power
From the outset of his career as a civil rights advocate, Marshall observed how law enforcement practices often targeted minority communities disproportionately. He understood that formal guarantees mean little if the machinery of justice can be used capriciously or punitively against the powerless. During his time on the Supreme Court, he consistently argued that constitutional protections—whether grounded in the Fourth Amendment’s shield against unreasonable searches, the Fifth Amendment’s protection against self-incrimination, or the Sixth Amendment’s guarantee of effective counsel—should be interpreted expansively to offset entrenched power imbalances.
Ensuring a Level Playing Field
Marshall viewed the Constitution as a counterbalance to societal inequities, so he resisted any narrowing of procedural safeguards that might disadvantage indigent or minority defendants. His dissents repeatedly underscored how subtle erosions of defendant protections—like lax standards for issuing warrants or obtaining confessions—could perpetuate systemic bias. He believed that only by enforcing these rights robustly could the criminal justice process serve as a fair forum for all citizens, irrespective of race or economic status.
Emphasis on Procedural Regularity and Disclosure
Marshall’s jurisprudence was also marked by an insistence that courts and prosecutors fulfill their constitutional duties of procedural regularity. He believed that when the government withholds exculpatory evidence or relies on dubious interrogation tactics, it undermines the legitimacy of the entire justice system. Cases such as United States v. Bagley (1985), where Marshall joined Justice Harry Blackmun’s dissent stressing strict prosecutorial disclosure obligations, illustrate his conviction that fair process is not a luxury, but the essence of constitutional criminal procedure.
These core principles laid the groundwork for the subsequent evolution of criminal procedure doctrine. As the Court’s majority moved in a more conservative direction during and after Marshall’s tenure, many of his positions ended up in dissents—dissents that later generations of jurists, lawyers, and scholars have frequently cited as prescient critiques of the system’s drift toward greater prosecutorial and police discretion.
The Warren Court Legacy and Early Shifts
Well before Thurgood Marshall joined the Supreme Court, Mapp v. Ohio had extended the exclusionary rule—barring illegally obtained evidence from trial—to the states. This expansion drastically altered police practices. During the 1970s and 1980s, however, the Court introduced exceptions that gradually limited the exclusionary rule’s reach. While Marshall consistently resisted these carve-outs, many of his colleagues began to accept the notion that some police mistakes or “good faith” errors did not warrant total suppression of evidence.
United States v. Leon (1984) and Massachusetts v. Sheppard (1984)
These cases carved out the “good faith” exception to the exclusionary rule. Leon held that evidence obtained via a search warrant later found invalid could still be used in trial, so long as the police acted in “objective good faith.” Marshall dissented, warning that this exception risked eroding deterrence: if police and magistrates became less vigilant about constitutional requirements, the Fourth Amendment’s protections would effectively soften. Over time, Leon’s rationale expanded as subsequent courts deemed various police or clerical errors excusable.
Nix v. Williams (1984) and Inevitable Discovery
Decided the same year as Leon, Nix introduced the “inevitable discovery” doctrine, allowing unlawfully obtained evidence if the prosecution could show it would have been found through lawful means eventually. Again, Marshall dissented. He argued that minimizing the consequences of police misconduct could embolden officers to disregard constitutional rules, expecting that courts might salvage the evidence anyway. These exceptions ultimately foreshadowed how the Rehnquist Court would adopt a more pragmatic—some would say lenient—approach to law enforcement errors, departing from Marshall’s stricter insistence on deterrence.
Expanding Police Discretion in the Vehicle Context
Another area where post-Marshall jurisprudence diverged from his robust reading of Fourth Amendment rights was in the regulation of traffic stops and vehicle searches.
Michigan Dept. of State Police v. Sitz (1990)
While Marshall was still on the Court, Sitz upheld sobriety checkpoints on Fourth Amendment grounds, concluding that the state’s interest in preventing drunk driving outweighed individual privacy intrusions. In dissent, Marshall criticized the majority for approving suspicionless stops. He cautioned that giving police such authority—no matter how well-intended—set a dangerous precedent for future expansions of checkpoint logic. Post-Sitz, states increasingly relied on checkpoint and “special needs” rationales for additional intrusion.
Whren v. United States (1996)
Decided after Marshall’s retirement, Whren permitted police to use minor traffic violations as a pretext for vehicle stops to search for more serious criminal activity, effectively greenlighting widespread discretionary stops that critics argue often target minority drivers. Many scholars trace the vulnerability of such a decision back to the Court’s earlier acceptance of broad law enforcement latitude, which Marshall had long opposed. Though the majority in Whren insisted that subjective police motives were irrelevant under the Fourth Amendment, Marshall’s outlook would have focused on the real-world consequences for racial profiling and selective enforcement.
The “Reasonableness” Trend
The Rehnquist and Roberts Courts increasingly framed the Fourth Amendment inquiry in terms of “reasonableness,” rather than strict warrant requirements. Cases like Illinois v. Rodriguez (1990), Maryland v. Buie (1990), and Kentucky v. King (2011) exemplify the Court’s willingness to uphold warrantless entries based on a flexible interpretation of exigent circumstances, consent, or safety concerns. Although Marshall’s direct influence waned after his departure, his cautionary dissents presaged the dangers of a nebulous reasonableness standard that can be expanded to justify almost any invasive search. Critics who share Marshall’s skepticism argue that these developments erode the structural protection the Fourth Amendment was designed to offer, leaving lower courts to parse often subjective factual scenarios with minimal guidance or restraint.
Marshall’s Consistent Support for Miranda
The Warren Court’s Miranda v. Arizona revolutionized police interrogation by requiring warnings about self-incrimination and the right to counsel before questioning. Although decided before Marshall joined the Court, he enthusiastically supported Miranda’s rationale—believing that custodial interrogation was inherently coercive and that proper safeguards were essential for truthful, voluntary confessions. Throughout the 1970s and 1980s, as colleagues questioned Miranda’s scope, Marshall repeatedly stressed the importance of unwavering compliance. Even “benign” modifications, he feared, could open the door to manipulative interrogation practices.
Post-Marshall Challenges and Exceptions
After Marshall left, the Court issued decisions that chipped away at Miranda’s bright-line rules:
New York v. Quarles (1984) (before his retirement, but reflecting the emerging trend) introduced the “public safety” exception, allowing police to question suspects without warnings if there was an immediate threat. Marshall dissented, warning against injecting subjective and malleable standards that diluted Miranda’s clarity.
Oregon v. Hass (1975) and Oregon v. Elstad (1985) limited the scope of Miranda’s exclusionary rule by permitting otherwise unwarned statements to be used for impeachment or admitting “subsequent” confessions as long as the initial unwarned statement did not taint the latter. Marshall consistently argued that such “exceptions” neutered Miranda’s deterrent effect, encouraging officers to circumvent the spirit of the ruling.
Dickerson v. United States (2000) reaffirmed Miranda’s constitutional status, rejecting congressional attempts to overrule it. Although Marshall had been off the bench for nearly a decade, the Court’s majority effectively validated his stance that Miranda warnings are constitutionally grounded, not mere prophylactic devices. Yet subsequent rulings, such as Florida v. Powell (2010), offered flexible interpretations of Miranda’s wording, suggesting that while the core requirement survived, the edges of the doctrine remained contested territory.
By the early 21st century, Miranda endures in name. Still, critics argue that piecemeal exceptions—some introduced or expanded after Marshall’s departure—eroded its practical force, leaving defendants vulnerable to overreach. Marshall’s repeated warnings in earlier decades anticipated precisely this outcome: once the Court signals willingness to bend Miranda, law enforcement can exploit the gray areas.
Brady and Bagley: The Foundations
Even before Marshall’s Supreme Court days, Brady v. Maryland (1963) had established that due process requires prosecutors to disclose exculpatory evidence. Marshall joined the Court at a juncture when Brady’s contours were still uncertain. Over time, he consistently advocated for a strong reading of Brady, believing that a just trial could not exist if the state hid critical evidence. In United States v. Agurs (1976), the Court attempted to clarify when evidence is “material,” but Marshall dissented in part, arguing for a broader standard that erred on the side of disclosure.
United States v. Bagley (1985) tested whether impeachment evidence fell under Brady’s umbrella, and what standard for “materiality” governed undisclosed evidence. The plurality held that impeachment evidence must be disclosed if there is a “reasonable probability” that, had it been disclosed, the result of the proceeding would have been different. Justice Blackmun’s dissent (joined by Marshall) advocated a more stringent rule requiring automatic reversal in certain instances of undisclosed impeachment material. Marshall feared that the “reasonable probability” test allowed prosecutors too much leeway to justify non-disclosure. After all, how can a defendant or reviewing court confidently assess the effect of evidence that was hidden all along?
Post-Bagley Progeny
Subsequent cases illustrate how the Supreme Court’s chosen standard in Bagley shapes prosecutorial conduct to this day:
Kyles v. Whitley (1995) reinforced the “reasonable probability” approach but emphasized that courts must view withheld evidence cumulatively. Even so, the Kyles majority did not adopt the automatic rule that Marshall had championed. Instead, it placed on courts the task of determining whether withheld evidence, collectively, undermines confidence in the verdict.
Strickler v. Greene (1999) reaffirmed Bagley’s approach, requiring defendants to prove that suppressed evidence was favorable, material, and that the prosecution had indeed suppressed it. Though the Court’s majority saw this as a workable standard, critics (echoing Marshall’s earlier dissents) believe the burden often falls too heavily on defendants to reconstruct how undisclosed evidence might have influenced the outcome—an inherently speculative exercise.
Turner v. United States (2017) offered yet another glimpse into how the Court applies Bagley. In Turner, the Court upheld murder convictions despite prosecutors withholding potentially exculpatory evidence. It concluded that, collectively, the undisclosed evidence did not create a reasonable probability of a different outcome. Dissenters cited concerns that this standard is too forgiving of prosecutorial lapses, again reflecting Marshall’s critique that the “reasonable probability” test can trivialize due process when the withheld evidence is not obviously dramatic on its face, but might have changed the trial’s trajectory.
Taken together, these progeny cases demonstrate that while Brady and Bagley remain the law of the land, the burden of proving materiality can be formidable. Marshall’s push for an automatic or near-automatic reversal rule for significant nondisclosures never became doctrine, yet his arguments remain potent in reform discussions. Many state courts, for instance, have experimented with “open file” policies or more stringent disclosure rules in recognition of the systemic challenges inherent in post-trial materiality assessments.
Expanding Gideon but Grappling with Implementation
Though Gideon v. Wainwright (1963) preceded Marshall’s arrival, he strongly supported its holding that indigent defendants must receive appointed counsel in felony cases. Subsequent rulings extended Gideon to certain misdemeanors involving the threat of jail time. Marshall concurred in these expansions, urging that effective counsel was crucial not just in theory but in real practice. He dissented in some cases where the Court refused to apply Gideon’s logic more broadly—particularly when defendants faced severe collateral consequences without counsel.
Strickland v. Washington (1984) and Ineffective Assistance
One of the biggest post-Gideon developments was Strickland v. Washington, which defined the standard for “ineffective assistance of counsel.” Defendants must show (1) counsel’s performance fell below an “objective standard of reasonableness,” and (2) there is a “reasonable probability” that the deficient performance affected the outcome. Although Marshall was still on the Court, he dissented from aspects of the Strickland framework, voicing concern that it set too high a bar, allowing severely deficient lawyering to pass constitutional muster so long as courts found the errors non-prejudicial.
Subsequent decisions like Lockhart v. Fretwell (1993) and Williams v. Taylor (2000) have tested Strickland’s boundaries. Despite incremental clarifications, the standard remains challenging for defendants to meet—courts often presume counsel’s performance was adequate. This outcome partially vindicates Marshall’s skepticism: once the Court entrenched a malleable prejudice standard, it became an uphill battle for defendants to demonstrate a “reasonable probability” of a different verdict, even in cases of glaring attorney misconduct or inexperience.
Recent Right-to-Counsel Cases
Though the modern Court still recognizes the Sixth Amendment’s broad significance, post-Marshall jurisprudence has not dramatically broadened Gideon’s scope. Cases like Padilla v. Kentucky (2010) extended Strickland to cover counsel’s failure to advise about immigration consequences, indicating some willingness to adapt the right to counsel in a changing legal landscape. However, the baseline remains that public defender systems across many states struggle with underfunding and immense caseloads. While not all of these systemic deficiencies are litigated at the Supreme Court level, they highlight a tension Marshall identified: a formal right to counsel means little if counsel lacks the resources to mount a meaningful defense.
Criminal Justice Reform Movements
In the decades after Marshall’s tenure, a variety of criminal justice reform movements emerged, often citing the very concerns Marshall raised in his opinions and dissents. These include:
Open-File Discovery: Many prosecutors’ offices and some state legislatures have adopted or proposed expansive discovery rules, aiming to ensure that Brady and Bagley principles are fulfilled more robustly. Marshall’s warnings that a narrow reading of materiality invites trial by ambush continue to echo in calls for transparent prosecutorial practices.
Rethinking Police Accountability: As the exclusionary rule’s scope shrank, critics have pushed for alternative accountability mechanisms—civil suits, improved training, body cameras—citing the risk of normalizing unconstitutional searches. Marshall’s emphasis on deterrence resonates in contemporary debates over how best to incentivize lawful police conduct without unduly freeing the guilty.
Indigent Defense Reform: The chronic underfunding of public defender systems, combined with Strickland’s stringent prejudice requirement, has prompted organizations to champion workload caps, higher funding, and improved training for defense attorneys. Many of these efforts explicitly or implicitly build on Marshall’s proposition that effective counsel is a linchpin of fairness, not a procedural afterthought.
Scholarly Recognition and Judicial Citations
Marshall’s dissents in Leon, Bagley, and other major cases have proven enduring citations for those who argue the Court has swung too far in favor of convenience for law enforcement. Although rarely adopted wholesale, his reasoning frequently surfaces in both federal and state appellate opinions as a counterpoint, urging narrower exceptions or more robust disclosure. This dynamic underscores the living nature of dissent: even if Marshall’s views were in the minority at the time, they persist as guiding critiques that can influence future doctrinal shifts.
Modern Supreme Court Stance
Under Chief Justice John Roberts, the Court has occasionally reaffirmed or slightly reinforced some defendant protections—Missouri v. Frye (2012) and Lafler v. Cooper (2012), for example, extended Sixth Amendment claims into the realm of plea bargaining. Yet the general trajectory leans toward granting law enforcement broader authority, consistent with the conservative turn that began in the 1980s. Marshall’s approach, which insisted on strong prophylactic rules and minimal exceptions, remains a rallying cry for the Court’s liberal wing (when it exists in close cases) and for reform-minded jurists in the lower courts.
Thurgood Marshall’s criminal procedure legacy rests on a deceptively simple premise: constitutional rights must be more than theoretical statements; they must tangibly protect real people, especially the vulnerable, from the awesome power of the state. That principle guided his stances on issues from police searches to prosecutorial disclosure. While shifting Court majorities often placed him in dissent, the subsequent decades of jurisprudence reveal a persistent interplay between Marshall’s robust vision of defendants’ rights and the Court’s gradual acceptance of law enforcement–friendly doctrines.
Indeed, many of the doctrinal battles that define today’s criminal procedure landscape trace back to Marshall’s era. The good faith exception, expanded vehicle searches, narrower Miranda protections, a limited reading of Brady and Bagley, and a high hurdle for proving ineffective counsel all illustrate a more lenient approach than Marshall would have endorsed. Nevertheless, his arguments continue to shape debates over whether and how to reinvigorate the Warren Court’s ideals—or to at least preserve what remains.
Reformers, advocates, and critical scholars regularly invoke Marshall’s dissents, reminding the legal community that a system tilted toward expediency or prosecutorial dominance risks eroding essential liberties. They note that Marshall anticipated many of the negative consequences that have since materialized: racial profiling under broad traffic-stop rules, wrongful convictions tied to undisclosed evidence, and under resourced defense counsel unable to safeguard the accused. In that light, his legacy endures not only as a testament to his era but also as a forward-looking critique of criminal procedure’s evolution.
Ultimately, the tension between Marshall’s robust protective philosophy and the Court’s incremental acceptance of expanded police and prosecutorial authority remains at the heart of modern criminal procedure debates. Whether through legislative reform, innovative state constitutional interpretations, or future Supreme Court reconsiderations, the ideals Marshall championed still shape the quest for a fair system—one in which constitutional rights are not hollow promises but living assurances that justice, not mere efficiency, prevails.