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Top 10 Court Cases That Changed the U.S. Justice System

by Toby Oliva
fact checked by Rachel Jones

The United States justice system is full of landmark cases that have shaped how we understand and apply the law. Let’s explore 10 of the most critical court cases that changed the justice system.

Related: Top 10 Times The US Government Took Inanimate Objects To Court

10 Caniglia v. Strom (2021)

Caniglia v Strom (2021)


In 2015, Edward Caniglia had an argument with his wife, where he allegedly placed a gun on the table and told his wife to shoot him. Rather than comply, she left and called the police, asking them to complete a welfare check.

Caniglia was taken to the hospital for a psychiatric evaluation, stipulating that the authorities would not take his guns. But police entered Caniglia’s home without a warrant and seized his firearms.

Caniglia sued the police, arguing that the warrantless search and seizure violated his Fourth Amendment rights. The police claimed that they acted under the “community caretaking” exception to the Fourth Amendment, which allowed them to conduct a search and seizure for non-criminal purposes.


The Supreme Court ruled in favor of Caniglia, stating that the “community caretaking” exception did not apply to a private home and that the police violated his Fourth Amendment.


The Court’s decision reaffirms the importance of Fourth Amendment protections for private homes and personal property, limiting the scope of the “community caretaking” exception and strengthening the requirement for police to obtain a warrant before entering a private home.

9 Gideon v. Wainwright (1963)

Why You Get a Lawyer If You Can’t Afford One | Gideon v. Wainwright


In 1961, Clarence Gideon was arrested and charged with breaking and entering. Gideon could not afford a lawyer and was ultimately convicted and sentenced to five years in prison.

Gideon petitioned the U.S. Supreme Court, arguing that his Sixth Amendment right to counsel had been violated. Gideon argued that he should have been provided with a lawyer, even though he could not afford one.


The Supreme Court agreed with Gideon, ruling that the Sixth Amendment guarantees the right to counsel for defendants who cannot afford one.


Gideon v. Wainwright established a right to counsel for all criminal defendants, regardless of their ability to pay. The ruling expanded criminal defendants’ rights and helped ensure that poor and marginalized individuals are not unfairly targeted or punished.

8 Miranda v. Arizona (1966)

Miranda v. Arizona Explained


Ernesto Miranda was arrested and interrogated by police concerning a rape and kidnapping. During the interrogation, Miranda confessed to the crimes. However, the cops never told him about his right to remain silent or his ability to have an attorney present.

The prosecution used his confession as evidence, and he was sentenced to 20-30 years in prison.

Miranda’s lawyers appealed, arguing that the police had violated his Fifth Amendment right against self-incrimination and his Sixth Amendment right to counsel by not informing him of those rights.


The Court ruled that police must inform suspects of their right to remain silent and their right to counsel before interrogation. Additionally, any statements obtained in violation of these rights cannot be used against the individual.


Miranda v. Arizona strengthened protections for criminal defendants and established clear guidelines for the police during interrogations. It is a crucial safeguard against coerced confessions and other abuses of power.

7 Edwards v. Vannoy (2021)

Edwards v Vannoy (2021)


In 2007, Tarahrick Edwards was convicted of armed robbery and rape. Edwards appealed his conviction, arguing that the court minimized minority representation, allowing only one black individual to sit on the jury.

One juror voted to acquit Edwards, but due to Louisiana non-unanimous jury law, he was sentenced to life in prison. Edwards challenged his conviction stating that Louisiana’s non-unanimous jury conviction laws were unconstitutional.


After repeated attempts to overturn his conviction, the Supreme Court stated that non-unanimous jury verdicts could not be applied retroactively.


Edwards v. Vannoy clarified the retroactive application of the law in Ramos v. Louisiana (2020). The decision allows individuals convicted by non-unanimous juries to seek relief and challenge their convictions as long as the case happens after 2020.

6 Furman v. Georgia (1972)

Furman v. Georgia (1972) | A Moratorium on the Death Penalty


In 1967, William Furman, a black man, was arrested for murder after he broke into a home and killed the homeowner. Furman was convicted, and the trial judge imposed the death penalty. However, under Georgia law at the time, the death penalty was not mandatory for anyone convicted of murder, leaving the sentencing to the discretion of the judge or jury.

Furman appealed his sentence to the U.S. Supreme Court, arguing that Georgia’s death penalty statute was unconstitutional because it allowed for arbitrary and discriminatory application. Specifically, Furman argued that the death penalty was more likely to be imposed on defendants who were black, poor, or otherwise disadvantaged.


In a 5-4 decision, the Supreme Court held that Georgia’s death penalty statute, as well as the death penalty statutes of other states, violated the Eighth Amendment’s prohibition against cruel and unusual punishment. The Court stated the death penalty was being imposed with no standards to guide its application and that it was unconstitutional.

The Court did not, however, hold that the death penalty itself was unconstitutional. Instead, it held that how it was being imposed was unconstitutional.


Furman v. Georgia forced states to revise their capital punishment statutes to include safeguards against discriminatory applications. In response, many states adopted new laws that required juries to consider mitigating factors before imposing the death penalty and provided an appellate review of death sentences.

5 United States v. Nixon (1974)

Is the President Above the Law? | United States v. Nixon


In 1972, a group of burglars broke into the Democratic National Committee headquarters at the Watergate office complex in Washington, D.C. The burglars were later connected to President Richard Nixon’s re-election campaign. Soon after, an investigation began into the administration’s role in the break-in and the subsequent cover-up.

Special prosecutor Archibald Cox issued a subpoena for Nixon to release recordings of conversations that had taken place in the Oval Office. Nixon refused to comply with the subpoena, citing executive privilege and arguing that the tapes contained confidential information that would harm national security if released.


In an 8-0 decision, the Supreme Court held that Nixon had no authority to withhold evidence relevant to a criminal trial. The Court rejected Nixon’s claims of executive privilege, finding that while the president had a constitutional duty to protect national security, this duty did not give him the power to override the law or obstruct justice.

As a result of the decision, Nixon was forced to release the recordings, which contained incriminating evidence that ultimately led to his resignation.


The United States v. Nixon decision established that no one, not even the president, is above the law. The decision affirmed the judiciary’s power to hold the executive branch accountable and require the release of evidence in criminal trials.

The case remains an important precedent for cases involving executive privilege and the separation of powers between branches of government.

4 United States v. Leon (1984)

United States v. Leon Case Brief Summary | Law Case Explained


In 1981, police officers in Los Angeles obtained a search warrant based on information from a reliable informant. However, the warrant was later found to be invalid due to a technical error.

Nonetheless, the officers searched Leon’s home and found drugs and other evidence of drug trafficking. Leon was charged with drug offenses.


The case went to the U.S. Supreme Court; they created a “good faith” exception to the exclusionary rule, which allows evidence to be used at trial even if the warrant was later found to be defective, as long as the police acted in good faith when obtaining the warrant.


Some have praised the decision in United States v. Leon as a necessary step to balance the need for law enforcement with the protection of individual rights. In contrast, others have criticized it as weakening the Fourth Amendment protections against unreasonable searches and seizures.

3 Batson v. Kentucky (1986)

Batson v Kentucky (1986)


In 1982, James Batson, a black man, was on trial for burglary and receiving stolen goods. During jury selection, the prosecutor used challenges to strike all four black potential jurors from the jury pool, leaving an all-white jury.

Batson’s defense attorneys objected to the prosecutor’s use of peremptory challenges, arguing that it violated Batson’s rights under the Fourteenth Amendment’s Equal Protection Clause. The trial court rejected the objection, and Batson was convicted and sentenced to prison.

On appeal, Batson argued that the prosecutor’s use of peremptory challenges to strike potential jurors based on race was unconstitutional.


The U.S. Supreme Court ruled that the prosecutor’s use of peremptory challenges to exclude jurors based solely on their race violated the Equal Protection Clause of the Fourteenth Amendment. The Court held that a defendant has the right to a jury pool selected without regard to race and that challenges cannot be used to exclude jurors based on race or ethnicity.


Batson v. Kentucky established an important precedent for ensuring racial fairness in jury selection. It signaled a shift away from the historical practice of excluding jurors based on race, and it established clear guidelines for preventing discrimination in the jury selection process.

The ruling has been hailed as a significant step forward in the fight for racial equality in the criminal justice system. However, some critics argue that the Batson rule has been difficult to enforce and has not gone far enough in addressing issues of racial bias in the criminal justice system.

2 New York Times Co. v. Sullivan (1964)

New York Times v. Sullivan Explained


In 1960, the Civil Rights Movement placed a full-page ad in the New York Times that criticized the treatment of civil rights protesters in the South.

L. B. Sullivan, the city commissioner of Montgomery, Alabama, sued the New York Times for defamation, claiming that the ad contained false statements about him and harmed his reputation. At trial, the jury awarded Sullivan $500,000 in damages.


The case reached the U.S. Supreme Court, ruling that the First Amendment’s protection of free speech and press extends to statements about public officials. Such officials must prove actual malice (i.e., knowledge of falsity or reckless disregard for the truth) to recover damages.


New York Times Co. v. Sullivan has significantly impacted the freedom of the press and the ability of individuals to criticize public officials without fear of being sued for defamation. The “actual malice” standard set by the Court became an essential element of First Amendment law. It has been applied to a wide range of cases involving media coverage of public officials and matters of public concern.

1 Kahler v. Kansas (2020)

Kahler v. Kansas [SCOTUSbrief]


In 2009, James Kahler shot and killed his estranged wife, her grandmother, and his two teenage daughters. Kahler was charged with capital murder, found guilty, and sentenced to death.

Kahler’s defense team argued that he was not responsible for his actions due to his mental illness. However, the trial judge instructed the jury that mental illness alone was insufficient to negate intent or justify a lesser charge of second-degree murder.

Kahler appealed his conviction, arguing that the trial judge’s instructions violated his Eighth Amendment rights against cruel and unusual punishment and his Fourteenth Amendment right to due process.


In a 6-3 decision, the U.S. Supreme Court held that the Kansas law prohibiting the use of mental illness as a defense to criminal charges did not violate the Eighth or Fourteenth Amendments.

The Court noted that while mental illness can mitigate criminal sentencing, it does not negate the mens rea or intent required for a conviction.

The Court further held that the specific jury instructions given in Kahler’s case did not violate his constitutional rights, as they did not preclude the consideration of his mental illness as a mitigating factor in sentencing.


Some advocates have criticized the decision in Kahler v. Kansas, arguing that the ruling could discourage defendants from seeking help for their mental health issues and lead to more severe punishments for those with mental illnesses.

However, the decision also reflects a longstanding legal principle that criminal intent is a critical element of criminal law and that mental illness, while a mitigating factor, cannot excuse criminal behavior entirely.

fact checked by Rachel Jones