Hanger v. Abbott 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, John Hanger, was held in a federal prison in the District of Columbia. Hanger sought a writ of habeas corpus from the Supreme Court of the District of Columbia, but the court refused to issue the writ. Hanger then appealed to the Supreme Court of the United States. 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 writs of habeas corpus 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 state court should not be allowed to interfere with the federal government's power to imprison individuals. The Court's decision in Hanger v. Abbott established that the state court did not have the authority to issue a writ of habeas corpus to a prisoner held in a federal prison. This decision has been cited in numerous cases since then, and it has been used to support the idea that the federal government has the power to imprison individuals without interference from the states.

In the case of Hanger v. Abbott, Justice Field delivered a dissenting opinion in which he argued that the decision of the Supreme Court should be reversed and remanded to the lower court. He disagreed with Chief Justice Chase's majority opinion that held that an agreement between two parties was void because it violated public policy. Instead, Field argued that such agreements were not necessarily invalid if they did not violate any existing laws or statutes; rather, their validity depended on whether they were fair and reasonable for both parties involved. Furthermore, he contended that even if one party had acted improperly by attempting to take advantage of another party through an unfair contract provision, this would still not render the entire agreement void as long as other parts of it remained valid and enforceable under law. In conclusion, Field believed there was no legal basis for declaring contracts like those at issue in this case invalid simply because they may have been deemed contrary to public policy or morals by some people; instead each contract must be judged on its own merits based upon applicable laws and regulations before determining its validity or lack thereof.