O'Brien v. Perry was a case heard by the United States Supreme Court in 1861. The case concerned whether or not an individual could be held liable for damages caused to another person's property while attempting to enforce a court order issued against them. In this particular instance, O'Brien had been ordered by the court to pay certain debts and when he failed to do so, Perry attempted to seize his property as payment for those debts. During the seizure process, some of O'Brien's possessions were damaged or destroyed and he subsequently sued Perry for compensation. The Supreme Court ultimately ruled that individuals enforcing court orders are not personally liable if they act within their authority granted by law and without malice or negligence; however, they may still be held responsible if it is found that their actions exceeded what was necessary under the circumstances of the situation at hand.

In O'Brien v. Perry, the Supreme Court was asked to decide whether a state statute that allowed for the sale of property belonging to an insolvent debtor was constitutional. The majority opinion held that it did not violate any provision of the Constitution and thus upheld the law in question. However, Justice Nelson dissented from this decision on two grounds: firstly, he argued that such a law violated Article I Section 10 of the Constitution which prohibits states from passing laws impairing contracts; secondly, he argued that even if there were no violation of Article I Section 10 then due process would still be denied as creditors had no opportunity to contest or challenge their debtors’ claims before they were sold off by court order. In conclusion, Justice Nelson believed that allowing such sales without proper notice and hearing constituted a deprivation of rights without due process and should therefore have been struck down by the Court as unconstitutional.