Baldwin v. Hale was a United States Supreme Court case in which the court held that an individual's right to contract is protected by the Constitution, and that state laws cannot interfere with this right without violating due process of law. The plaintiff, Baldwin, had entered into a contract with Hale for the sale of certain real estate owned by Baldwin. However, before he could complete payment on the property as agreed upon in their contract, Alabama passed a statute voiding all contracts made between slaves and free persons unless approved by two justices of peace or one justice and two witnesses. Since neither party involved were slaves nor did they have any knowledge about such statutes when entering into their agreement, they argued it was unconstitutional for Alabama to retroactively apply this law to them after-the-fact since it violated both parties' rights under due process clause of the 14th Amendment. The Supreme Court ultimately sided with Baldwin and ruled that states may not pass laws interfering with individuals’ contractual rights without violating due process protections provided under federal law; thus invalidating Alabama's statute at issue here as unconstitutional.

In Baldwin v. Hale, the Supreme Court was asked to decide whether a state court had jurisdiction over a case involving an alleged breach of contract between citizens of different states. The majority opinion held that the state court did have jurisdiction and affirmed the judgment below. However, Justice Grier dissented from this decision on two grounds: firstly, he argued that there was no evidence in the record showing that either party had consented to be sued in a state court; secondly, he asserted that it would be unconstitutional for one sovereign power (in this case New York) to exercise judicial authority over another sovereign power (Pennsylvania). He concluded by saying "the Constitution has not given any such powers." Thus, Justice Grier's dissent argued against allowing state courts to exercise jurisdiction over cases involving citizens of other states without their consent or constitutional authorization.