Heckers v. Fowler 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 any state legislation attempting to limit or restrict this right must be reasonable and not arbitrary. The case involved two parties who had entered into a contract for the sale of certain goods; however, Pennsylvania law prohibited such contracts from being enforced if they were made on Sunday. As such, Heckers sued Fowler for breach of contract when he failed to fulfill his obligations under their agreement. The Supreme Court found in favor of Heckers, ruling that while states may pass laws regulating contracts so long as those regulations are reasonable and do not arbitrarily interfere with individuals' rights to enter into agreements freely, Pennsylvania's Sunday restriction did just that - it interfered with citizens' ability to make voluntary contractual arrangements without good cause or justification.

In Hecker's v. Fowler, the Supreme Court was asked to decide whether a state court had jurisdiction over a case involving citizens of different states. The majority opinion held that the state court did have jurisdiction and could hear the case. However, Justice Field dissented from this decision and argued that it violated Article III of the Constitution which grants exclusive federal judicial power in cases between citizens of different states. He further argued that Congress has not given any authority to state courts for such matters, so they do not have any right or power to act on them either directly or indirectly through their own laws or decisions. Furthermore, he stated that allowing state courts to exercise such powers would be an encroachment upon federal judicial authority and undermine its independence as well as create confusion among litigants who may find themselves subject to two separate jurisdictions at once depending on where they are located when filing suit against each other. In conclusion, Justice Field believed strongly in upholding constitutional principles by limiting jurisdictional boundaries between federal and state courts whenever possible in order protect both parties' rights under law equally regardless of location