Porter v. Beard is a United States Supreme Court case that dealt with the issue of whether a state court had the authority to order a prisoner to be executed by means of electrocution. The case arose when a Pennsylvania state court sentenced William Porter to death for the murder of his wife. Porter appealed the sentence, arguing that the court had no authority to order his execution by electrocution, as the state had not yet adopted a law authorizing the use of electrocution as a method of execution. The Supreme Court ultimately held that the state court did have the authority to order Porter's execution by electrocution. The Court reasoned that the state court had the power to order the execution by electrocution because the state had adopted a law authorizing the use of electrocution as a method of execution. The Court further noted that the state court had the authority to order the execution by electrocution because the state had not adopted any other method of execution. In conclusion, the Supreme Court held that the state court had the authority to order Porter's execution by electrocution. The Court reasoned that the state court had the power to order the execution by electrocution because the state had adopted a law authorizing the use of electrocution as a method of execution and had not adopted any other method of execution.

Justice Field delivered the dissenting opinion in Porter v. Beard, arguing that the court should not have granted habeas corpus to the petitioner. He argued that Congress had given state courts exclusive jurisdiction over cases involving prisoners held under a sentence of death and thus federal courts did not have authority to grant relief from such sentences. Furthermore, he noted that even if there were some constitutional issue involved in this case, it was up to Pennsylvania's Supreme Court to decide whether or not any constitutional rights had been violated by their decision and for them alone to determine what remedy would be available as a result of any violation found. Justice Field concluded his dissent by noting that while he sympathized with the petitioner's plight, granting him habeas corpus was beyond the power of this court and could only be done through an act of Congress or through action taken by Pennsylvania’s highest court.