However, it was not until 1968 that the Court applied the general principle to invalidate a state law which, in the absence of established federal policy, encroached on the country`s external interests. In Zschernig v. Miller503 the court struck down an Escheat law of Oregon that was to prevent the inheritance of citizens of communist countries. The law conditioned the inheritance of non-resident aliens on proof that the United States ass` . . .