Kosciuszko Armstrong, the appellant in this case, was appealing a decision by the Circuit Court of Pennsylvania. The lower court had ruled that Thaddeus Kosciususko's estate should be divided among his heirs according to Polish law rather than American law. Armstrong argued that since Kosciuszko had been an American citizen for many years before his death and he died without leaving any will or testamentary disposition of his property, it should be distributed according to the laws of Pennsylvania where he resided at the time of his death. The Supreme Court agreed with Armstrong and reversed the ruling from below stating that "the rule established by our courts is well settled; when persons die intestate within this country their estates are disposed of agreeably to its laws." This meant that all assets would go into probate and then distributed amongst those entitled under state law as opposed to foreign jurisdiction.

In the case of Kosciuszko Armstrong, Appellant v. Benjamin L. Lear, Administrator of Thaddeus Kosciususzko and Others, Chief Justice Marshall delivered a dissenting opinion in which he argued that the Court should not have dismissed the appeal on jurisdictional grounds. He noted that there was no dispute as to whether or not Armstrong had standing to bring suit against Lear; rather, his argument was based on an interpretation of state law regarding inheritance rights and succession laws. Marshall argued that since this issue involved interpreting state law it fell within the jurisdiction of federal courts and thus should be heard by them instead of being dismissed for lack of jurisdiction. Furthermore, he stated that if a decision were made at this stage without hearing all parties then it would create an injustice because those who may have been affected by such a ruling would never get their day in court due to procedural issues related to jurisdiction. Therefore, Marshall concluded with his belief that dismissing the appeal on jurisdictional grounds was wrong and urged for further consideration before any final judgment could be rendered in order to ensure justice is served properly according to both federal and state laws alike