Grisar v. McDowell 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 held in a federal prison. The case arose when a prisoner, Grisar, was held in a federal prison in the District of Columbia. Grisar sought a writ of habeas corpus from the state court of the District of Columbia, but the federal government argued that the state court did not have the authority to issue such a writ. The Supreme Court ultimately held that the state court did not have the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. The Court reasoned that the power to issue such a writ was a federal power, and that the state court did not have the authority to interfere with the federal government's power to imprison individuals. The Court also noted that the writ of habeas corpus was a fundamental right, and that the federal government had the exclusive power to protect this right. 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 held in a federal prison. The Court reasoned that the power to issue such a writ was a federal power, and that the state court did not have the authority to interfere with the federal government's power to imprison individuals.

In Grisar v. McDowell, the Supreme Court was tasked with determining whether a contract between two parties could be enforced if it had been made in violation of an existing state law. The majority opinion held that such contracts were not enforceable and should be declared void by the courts. However, Justice Field dissented from this decision on the grounds that there is no general rule prohibiting enforcement of contracts made in violation of state laws; rather, each case must be decided based on its own merits and circumstances. He argued that while some cases may warrant invalidation due to public policy considerations or other factors, others may still merit enforcement depending upon their individual facts and circumstances. Furthermore, he noted that even when a contract has been found to violate a statute’s letter or spirit, it can still stand as long as it does not conflict with any constitutional provision or federal law – something which he believed was true for this particular case at hand.