The Mellon v. Weiss case in 1925 revolved around the issue of estate taxation. The administrator of a deceased person's estate, Weiss, contested the federal government's assessment and collection of an estate tax on property transferred by the decedent before death but intended to take effect after death. The Supreme Court ruled in favor of Mellon, representing the federal government as Agent for Internal Revenue Service (IRS). It held that such transfers were indeed subject to federal estate taxes under existing law at that time. This decision affirmed that Congress had broad power to levy taxes within constitutional limits and clarified how these powers applied specifically to inheritance and gift laws.

The dissenting opinion in the case of Mellon v. Weiss argued that the majority's decision to allow a state law, which imposed an inheritance tax on property transferred by will or intestacy from a deceased resident of Pennsylvania to beneficiaries residing outside of the United States, was unconstitutional. The dissent contended that this ruling violated both due process and equal protection clauses under the Fourteenth Amendment because it discriminated against non-resident aliens solely based on their location. They believed that such discrimination had no rational basis and served only as an arbitrary distinction between different classes of people. Furthermore, they asserted that there were other ways for states to protect their interests without infraciously violating constitutional rights.