The U.S. Supreme Court case Zschernig v. Miller (1967) involved a challenge to an Oregon law that restricted the ability of nonresident aliens to inherit property unless their home country provided reciprocal rights to Americans and did not impose burdensome taxes or other restrictions on the inherited property. The plaintiffs, relatives of a deceased Oregon resident who were citizens of East Germany, argued that this law violated the Supremacy Clause because it interfered with the federal government's exclusive power over foreign affairs. The Supreme Court agreed with them in an 8-1 decision, ruling that even though states have some authority over inheritance laws, they cannot enact policies which intrude upon the federal government’s domain - in this case, international relations. The court found that by requiring state courts to evaluate foreign nations' treatment of American heirs as part of probate proceedings was essentially involving them in matters related directly to foreign policy and international relations – areas constitutionally assigned solely for Federal Government.

In the dissenting opinion for Zschernig v. Miller, Justice Harlan argued that the Oregon statute in question did not infringe upon federal powers to conduct foreign affairs and was therefore constitutional. He contended that the law merely regulated inheritance rights within its jurisdiction and did not involve any direct interaction with foreign governments or their officials. Furthermore, he asserted that it is a state's prerogative to determine how property within its borders should be distributed after death, including considerations of whether beneficiaries living under certain political systems can effectively receive and enjoy such inheritances. The majority’s decision, according to him, unnecessarily intruded on states' rights without clear evidence of interference with federal authority over international relations.