Johansson v. Stephenson was a United States Supreme Court case that dealt with the issue of whether a foreign judgment could be enforced in the United States. The case involved a dispute between a Swedish citizen, Johansson, and an American citizen, Stephenson, over a contract for the sale of a ship. Johansson had obtained a judgment in Sweden against Stephenson for the amount due under the contract. Johansson then sought to enforce the judgment in the United States. The Supreme Court held that the foreign judgment could not be enforced in the United States. The Court reasoned that the foreign judgment was not binding in the United States because it was not based on the laws of the United States. The Court noted that the foreign judgment was based on the laws of Sweden, which were not binding in the United States. The Court also noted that the foreign judgment was not based on any treaty between the United States and Sweden. The Court concluded that the foreign judgment could not be enforced in the United States. The Court noted that the foreign judgment could only be enforced in the United States if it was based on the laws of the United States or a treaty between the United States and the foreign country. Since neither of these conditions were met in this case, the foreign judgment could not be enforced in the United States.

Justice Harlan delivered the dissenting opinion in Johansson v. Stephenson, arguing that the court should have found for the plaintiff and awarded damages. He argued that under Missouri law, a contract was formed when an offer was made and accepted by both parties; this had been done in this case as well. Furthermore, he noted that even if there were some ambiguities or uncertainties surrounding the agreement between Johansson and Stephenson, it would still be enforceable because of its nature as a unilateral contract - one party makes an offer to another which can only be accepted by performing certain actions (in this case paying money). Therefore, Justice Harlan concluded that since all elements of a valid contract had been met here - including consideration from both sides - then Johansson should have been allowed to recover damages for breach of said contract.