Hartog v. Memory is a United States Supreme Court case that dealt with the issue of whether a state court had the authority to issue a writ of error to a federal court. The case involved a dispute between two parties, Hartog and Memory, over a contract for the sale of a steamboat. Hartog had sued Memory in a state court, and Memory had appealed the case to a federal court. The federal court had ruled in favor of Memory, and Hartog had then sought a writ of error from the state court. The Supreme Court held that the state court did not have the authority to issue a writ of error to a federal court. The Court reasoned that the state court was not a court of appeals for the federal court, and that the state court did not have the power to review the decisions of the federal court. The Court also noted that the state court had no jurisdiction over the subject matter of the dispute, and that the state court could not interfere with the decisions of the federal court. The Court's decision in Hartog v. Memory established that state courts do not have the authority to issue writs of error to federal courts. This decision has been cited in numerous subsequent cases, and it has been used to support the principle that state courts cannot interfere with the decisions of federal courts.

Justice Field delivered the dissenting opinion in Hartog v. Memory, arguing that the majority's decision was contrary to established precedent and would lead to a dangerous expansion of state power over private property rights. He argued that under prior decisions, such as Hall v. Wisconsin (1854), states could not tax or assess any interest in land held by non-residents without their consent; this included mortgages given by out-of-state lenders for real estate located within the state's borders. The majority had disregarded this precedent and instead allowed New York State to impose a mortgage tax on an out-of-state lender who had loaned money secured by real estate located within its boundaries, even though it did not have jurisdiction over the lender itself. Justice Field argued that allowing such taxation would open up a Pandora’s box of potential abuses from other states seeking to expand their taxing powers beyond what is constitutionally permissible and thus infringe upon individuals' right to own property free from government interference or regulation.