Lammers v. Nissen was a United States Supreme Court case that dealt with the issue of whether a state court had the authority to grant a divorce to a couple who had been married in another state. The case involved a couple, Mr. and Mrs. Lammers, who had been married in Iowa but had since moved to Nebraska. In Nebraska, the couple had filed for a divorce, but the state court denied their request. The couple then appealed to the Supreme Court, arguing that the state court had the authority to grant the divorce. The Supreme Court ultimately ruled in favor of the couple, finding that the state court did indeed have the authority to grant the divorce. The Court reasoned that the state court had the power to grant the divorce because the couple had been married in another state and the laws of the state in which they were married did not prohibit the granting of a divorce. The Court also noted that the state court had the power to grant the divorce because the couple had been living in Nebraska for some time and had established a residence there. In conclusion, the Supreme Court ruled that the state court had the authority to grant the divorce to the couple, Mr. and Mrs. Lammers. The Court found that the state court had the power to grant the divorce because the couple had been married in another state and the laws of the state in which they were married did not prohibit the granting of a divorce. Additionally, the Court noted that the couple had been living in Nebraska for some time and had established a residence there.

In Lammers v. Nissen, the Supreme Court was asked to decide whether a state court had jurisdiction over a case involving land located in two different states. The majority opinion held that the state court did not have jurisdiction because it lacked authority under the Constitution and laws of both states involved. Justice Field dissented from this decision, arguing that there was no reason why one state should be denied access to justice when another is allowed it. He argued that if Congress had intended for such an outcome, they would have explicitly stated so in their legislation or constitutional provisions. Furthermore, he noted that denying access to justice based on geography could lead to unequal treatment of citizens depending on where they lived and thus violate principles of equal protection enshrined in our nation's founding documents.