In The United States vs. Robert B. Neleigh, the Supreme Court was asked to decide whether a state court had jurisdiction over an indictment for treason against a Confederate soldier who had been arrested in Maryland and taken into custody by federal authorities before being released on bail. The Court held that the state court did not have jurisdiction because it lacked authority to try cases involving offenses committed outside of its own boundaries or those of another state, as well as crimes which were punishable under federal law only. Furthermore, since treason is considered an offense against the United States itself rather than any particular State, it could only be tried in a Federal court with proper jurisdiction over such matters. As such, this case established that states do not have power to prosecute individuals accused of committing acts of treason against the Union during times when civil war exists between two separate governments within one nation's borders.

In The United States vs. Robert B. Neleigh, the Supreme Court was asked to determine whether a federal court had jurisdiction over a case involving an alleged violation of state law by two individuals who were not citizens of that state. Justice Curtis delivered the dissenting opinion in which he argued that the Constitution did not grant Congress power to regulate private actions between individuals within any particular State and therefore it could not give authority to federal courts for such cases. He further stated that if Congress wanted this type of power, they would need to pass legislation specifically granting it or amend the Constitution accordingly. In conclusion, Justice Curtis believed that since there was no constitutional basis for giving jurisdiction over these types of cases to federal courts, then none should be granted in this instance either and thus affirmed his dissent from the majority opinion on this matter.