Ex parte Roberts was a United States Supreme Court case that dealt with the issue of habeas corpus. The case involved a man named William Roberts, who was arrested in the District of Columbia for the alleged crime of larceny. Roberts was denied a writ of habeas corpus by the Circuit Court of the District of Columbia, and he appealed to the Supreme Court. The Supreme Court held that the Circuit Court had erred in denying Roberts' writ of habeas corpus. The Court reasoned that the writ of habeas corpus was a fundamental right that could not be denied without due process of law. The Court further held that the Circuit Court had failed to provide Roberts with the necessary due process. As a result, the Supreme Court reversed the Circuit Court's decision and granted Roberts' writ of habeas corpus. In its decision, the Supreme Court established the principle that the writ of habeas corpus is a fundamental right that cannot be denied without due process of law. This decision has been cited in numerous subsequent cases, and it remains an important precedent in the area of habeas corpus.

In Ex Parte Roberts, the Supreme Court was asked to decide whether a writ of habeas corpus should be granted for an individual who had been convicted in Texas and sentenced to death. The majority opinion held that the writ should not be issued because it would interfere with state proceedings. Justice Field dissented from this decision, arguing that federal courts have jurisdiction over cases involving individuals who are being unlawfully detained by state authorities. He argued that Congress has given federal courts authority to issue writs of habeas corpus when necessary and therefore they must do so in this case as well. Furthermore, he noted that if the court did not intervene then an innocent man could potentially face execution without due process of law which is contrary to both constitutional principles and public policy.