In LaFlin v. Herrington et al., the Supreme Court of the United States ruled that a state court could not issue an injunction to prevent a federal court from exercising its jurisdiction over a case. The dispute arose when two parties, LaFlin and Herrington, were involved in litigation regarding title to certain lands located in Wisconsin. After filing suit in both state and federal courts, Herrington sought an injunction from the Wisconsin Circuit Court preventing further proceedings on the matter before any other tribunal until his claim was decided by that court. The Supreme Court held that such action violated Article III of the Constitution which grants exclusive jurisdiction over cases arising under federal law to U.S district courts and prohibits states from interfering with their proceedings or judgments. Therefore, it concluded that no state court had authority to enjoin proceedings pending before another tribunal established by Congress for this purpose

In LaFlin v. Herrington et al., the Supreme Court was asked to decide whether a state court had jurisdiction over an action brought by citizens of one state against citizens of another in which the amount in controversy exceeded $500. The majority opinion held that it did not, and Justice Grier dissented from this decision. He argued that states should have concurrent jurisdiction with federal courts when it comes to cases involving parties from different states, as long as they meet certain criteria such as having more than $500 at stake or being related to diversity of citizenship or admiralty law. Furthermore, he believed that Congress had intended for there to be concurrent jurisdiction between federal and state courts when passing the Judiciary Act of 1789, which established the current judicial system in America. In conclusion, Justice Grier argued that allowing both federal and state courts to hear cases would provide greater access for litigants who may not be able to afford filing fees associated with bringing their case before a federal court