Southern v. Hagood was a United States Supreme Court case that dealt with the issue of whether a state could tax the income of a non-resident. The case was brought by a resident of South Carolina, who argued that the state's income tax was unconstitutional because it taxed the income of non-residents. The Supreme Court held that the state could not tax the income of non-residents, as it would be a violation of the Due Process Clause of the Fourteenth Amendment. The Court reasoned that the state could not tax the income of non-residents without providing them with the same protections and benefits that it provided to its own citizens. The Court also held that the state could not tax the income of non-residents if it did not provide them with the same protections and benefits that it provided to its own citizens. The Court concluded that the state's income tax was unconstitutional and that the non-resident was not liable for the tax. This case established the principle that states cannot tax the income of non-residents without providing them with the same protections and benefits that it provides to its own citizens.

In the case of Southern v. Hagood, the Supreme Court was tasked with determining whether a state court had jurisdiction to hear an appeal from a federal district court decision in which it found that certain lands were public property and not subject to taxation by the State of Georgia. The majority opinion held that such appeals are within the exclusive jurisdiction of federal courts, while Justice Field dissented on behalf of himself and two other justices. He argued that states have concurrent jurisdiction over matters involving their own laws and taxes, as long as they do not interfere with or conflict with any existing federal law or regulation. Furthermore, he asserted that allowing state courts to review decisions made by lower federal courts would help ensure uniformity in legal interpretation across jurisdictions since different interpretations could lead to conflicting results if only one level is allowed access for review purposes. In conclusion, Justice Field believed that granting states concurrent jurisdiction over these types of cases would be beneficial both for ensuring consistency among rulings and protecting citizens’ rights under both state and national laws simultaneously.