Ex parte Royall is a United States Supreme Court case that dealt with the issue of whether a state court could deny a defendant the right to a jury trial in a criminal case. The case arose when a Virginia state court denied a defendant, William Royall, the right to a jury trial in a criminal case. Royall appealed the decision to the Supreme Court, arguing that the denial of a jury trial violated his rights under the Sixth Amendment of the United States Constitution. The Supreme Court agreed with Royall, ruling that the Sixth Amendment guarantees the right to a jury trial in all criminal cases. The Court noted that the right to a jury trial is a fundamental right that is essential to a fair trial and that the state court had violated Royall's rights by denying him a jury trial. The Court also noted that the right to a jury trial is a fundamental right that is essential to a fair trial and that the state court had violated Royall's rights by denying him a jury trial. The Court's decision in Ex parte Royall established the principle that the right to a jury trial is a fundamental right that must be respected by state courts. The decision also established that the Sixth Amendment guarantees the right to a jury trial in all criminal cases. The Court's decision in Ex parte Royall has been cited in numerous subsequent cases and has been an important precedent in the development of the right to a jury trial in the United States.

In Ex Parte Royall, the Supreme Court was tasked with determining whether a Virginia statute that excluded African Americans from jury service violated the Fourteenth Amendment. The majority opinion found that it did not violate the amendment because African Americans were still allowed to serve on juries in other parts of Virginia and thus had equal protection under the law. However, Justice Harlan dissented from this decision and argued that allowing some counties to exclude African American jurors while others could include them created an unequal system of justice. He further argued that such exclusionary practices denied African Americans their right to be judged by a jury of their peers as guaranteed by both state and federal constitutions. In his dissent, he stated: “The very fact…that one class is excluded from participation in any branch of government or public function tends directly to create distinctions based upon race or color” which violates both state and federal constitutional protections for all citizens regardless of race or color.