Shepard & Others v. Carrigan was a United States Supreme Court case that dealt with the issue of whether a state court had the authority to issue a writ of habeas corpus to a prisoner who had been convicted in a federal court. The case arose when the petitioner, Shepard, was convicted in a federal court for a crime committed in the state of Massachusetts. After his conviction, Shepard sought a writ of habeas corpus from the state court, arguing that his conviction was unconstitutional. The state court granted the writ, and the state of Massachusetts appealed to the Supreme Court. The Supreme Court held that the state court did not have the authority to issue a writ of habeas corpus to a prisoner convicted in a federal court. The Court reasoned that the writ of habeas corpus was a federal remedy, and that the state court did not have the power to interfere with a federal court's decision. The Court also noted that the writ of habeas corpus was a remedy for federal prisoners, and that the state court did not have the power to grant relief to a federal prisoner. In conclusion, the Supreme Court held that the state court did not have the authority to issue a writ of habeas corpus to a prisoner convicted in a federal court. The Court reasoned that the writ of habeas corpus was a federal remedy, and that the state court did not have the power to interfere with a federal court's decision. The Court also noted that the writ of habeas corpus was a remedy for federal prisoners, and that the state court did not have the power to grant relief to a federal prisoner.

In Shepard & Others v. Carrigan, the Supreme Court was tasked with determining whether a deed of trust executed by a debtor to secure payment of an antecedent debt was valid and enforceable against subsequent creditors. The majority opinion held that the deed of trust was not valid because it did not comply with certain statutory requirements in effect at the time it was executed. Justice Field dissented from this decision, arguing that while there were some technical deficiencies in the execution of the deed, they should be disregarded as immaterial given that all parties involved had acted in good faith and no one had been prejudiced by them. He argued further that if such minor defects could invalidate deeds then many innocent people would suffer harm due to their lack of knowledge or understanding about legal formalities required for executing documents like these deeds. Thus he concluded that equity demanded upholding this particular deed despite its technical imperfections since all parties involved had acted honestly and fairly throughout its creation process.