Hatch v. Oil Company was a United States Supreme Court case that addressed the issue of whether a state could impose a tax on a foreign corporation that was engaged in interstate commerce. The case was brought by the Oil Company, a foreign corporation, against the state of Louisiana, which had imposed a tax on the company's activities. The Supreme Court held that the state of Louisiana could not impose a tax on the Oil Company's activities, as it was engaged in interstate commerce. The Court reasoned that the tax was an unconstitutional burden on interstate commerce, as it would place an undue burden on the company's ability to conduct business in other states. The Court also noted that the tax was discriminatory, as it was imposed on foreign corporations and not on domestic corporations. The Court's decision in Hatch v. Oil Company established that states cannot impose taxes on foreign corporations that are engaged in interstate commerce. This decision has been cited in numerous cases since, and has been used to protect the rights of foreign corporations to conduct business in the United States without undue interference from state governments.

Justice Field delivered the dissenting opinion in Hatch v. Oil Company, arguing that the majority's decision was contrary to established law and precedent. He argued that a contract between two parties should be enforced as written, unless it is illegal or against public policy. In this case, he believed that there was no evidence of illegality or public policy violation; therefore, the contract should have been enforced according to its terms. Furthermore, Justice Field noted that if one party had breached their obligations under the agreement then they would be liable for damages but not necessarily for specific performance of any kind. He concluded by stating his belief that contracts are meant to protect both parties and when properly executed they should be honored accordingly regardless of whether either party has suffered an economic loss from non-performance on either side.