Consider the Fugitive Slave Laws during the antebellum period of American history. How would we expect judges of the past to decide these cases, where free states are obliged legally to send fugitive slaves back to their owners in slave states? What sort of theory of jurisprudence might we expect them to follow?

Thomas Sims was an African American who escaped from slavery and fled to Boston. He was arrested under the Fugitive Slave Law and appealed his case to the Supreme Court under a writ of habeas corpus to challenge his case before the court. The opinion of Justice Shaw in the Sims’ trial makes reference to the notion of states’ rights as a rule of law in the United States. Shaw writes that states have made implicit treaties amongst themselves, as implied by the constitution and its sources of law, that they will respect each other decisions and rights-claims to fugitive slaves. It is an implicit “act of state” doctrine that only when rights-claims are invalid by the light of the Constitution, the secondary rules of obligation, should judges uphold fugitive slaves’ claim to resist expedition to their previous owners in free states.

Chief Justice Shaw makes an appeal to the existing positive law, and to the principle of states’ rights in the case. Legal Positivists like John Austin would certainly have condemned Thomas Sims disobedience to the system of positive law and respected the court’s decision to uphold the acts of state in slave states like Georgia. Under Austin’s account, Thomas Sims’ is obliged to obey every command he is given, and correlatively, he has a duty to obey these commands. Legalistically, the Supremacy Clause of the Constitution guarantees that treaties ratified become the “supreme law of the land”, and Shaw implies that this treaty is applicable between states. By entering into this treaty, Shaw argues, Massachusetts must respect the decisions of Georgia. What guides Shaw’s decision is not mere opinion, such as expressed by a vague customary law based in broad sources and interpretations, but based in positive morality as it is, which is to say that in Sims’ case it is based in the sanction of the court.

As much as this is a decision based on Shaw’s own discretion, and level of understanding about the principles that ought to guide him in this process, Austin would reply that ‘law is law’ and as subjects in the relation between sovereign and subject, we are obliged to obey the law. The court’s decision is supported by promise or threat of injury if not obeyed. The idea that laws as such give us a reason to feel obliged (or to accept an internal point of view) is a truth so “simple and glaring” that “it seems idle to insist upon it.” For Thomas Sims to challenge the Fugitive Slave Laws is one thing, but if we insist they are, as the natural lawyer argues, not in fact laws (implying they are non-binding upon us) then we are talking “stark nonsense” and only being mischievous. If we say we “hate” the Fugitive Slave Laws, at least we are being honest, but we often say that they are not divinely-revealed laws as a way of abusing legal language.

Austin’s view is very unattractive, and Ronald Dworkin’s critique of legal positivism and his account of how judges decide hard cases is convincing.