Virginia v. West Virginia was a landmark Supreme Court case that established the principle of equitable apportionment of a state's debt. The case arose when Virginia attempted to secede from the Union during the Civil War, and the newly formed state of West Virginia was created from the western counties of Virginia. Virginia argued that West Virginia should be responsible for a portion of its pre-secession debt, while West Virginia argued that it should not be held liable for any of Virginia's debt. The Supreme Court ultimately sided with Virginia, ruling that West Virginia was liable for a portion of Virginia's pre-secession debt. The Court held that the debt should be apportioned equitably between the two states, taking into account the population and resources of each state. The Court also held that the debt should be apportioned in such a way that it would not be a burden on either state. This ruling established the principle of equitable apportionment of a state's debt, which has been applied in numerous cases since.

In Virginia v. West Virginia, the Supreme Court was tasked with determining whether or not Congress had the power to create a new state out of part of an existing one without consent from that original state. The majority opinion held that it did have such authority, but Justice Field dissented on several grounds. He argued that while Congress has broad powers over territories and states admitted into the Union, they do not extend to taking away territory from an existing state without its permission. Furthermore, he noted that if this decision were allowed to stand then any other portion of a state could be taken away by Congress at will and thus undermine both federalism and individual rights in those states as well as their ability to govern themselves effectively. Finally, he pointed out how allowing for such actions would also lead to potential conflicts between different parts of a single nation which would be detrimental for all involved parties.