The tendency of a principle to expand itself to the limit of its logic.

In reading (whatever the hell I manage to read in my spare time), ran across this.  More to say about it, but want to get it down now.

Korematsu was born on our soil, of parents born in Japan. The Constitution makes him a citizen of the United States by nativity, and a citizen of California by residence. No claim is made that he is not loyal to this country. There is no suggestion that, apart from the matter involved here, he is not law-abiding and well disposed. Korematsu, however, has been convicted of an act not commonly a crime. It consists merely of being present in the state whereof he is a citizen, near the place where he was born, and where all his life he has lived.

Even more unusual is the series of military orders which made this conduct a crime. They forbid such a one to remain, and they also forbid him to leave. They were so drawn that the only way Korematsu could avoid violation was to give himself up to the military authority. This meant submission to custody, examination, and transportation out of the territory, to be followed by indeterminate confinement in detention camps. . . .

A military order, however unconstitutional, is not apt to last longer than the military emergency. Even during that period, a succeeding commander may revoke it all. But once a judicial opinion rationalizes such an order to show that it conforms to the Constitution, or rather rationalizes the Constitution to show that the Constitution sanctions such an order, the Court for all time has validated the principle of racial discrimination in criminal procedure and of transplanting American citizens. The principle then lies about like a loaded weapon, ready for the hand of any authority that can bring forward a plausible claim of an urgent need. Every repetition imbeds that principle more deeply in our law and thinking and expands it to new purposes. All who observe the work of courts are familiar with what Judge Cardozo described as “the tendency of a principle to expand itself to the limit of its logic.” * A military commander may overstep the bounds of constitutionality, and it is an incident. But if we review and approve, that passing incident becomes the doctrine of the Constitution. There it has a generative power of its own, and all that it creates will be in its own image. Nothing better illustrates this danger than does the Court’s opinion in this case.

Justice Jackson, wrote this in his dissent from Korematsu v US (starting on page 322 US 243).