In the following report I shall concentrate on the law as pronounced by the United States Supreme Court, which has, within the sphere of judicial competence, the last say on the interpretation of the Constitution. The volume of significant litigation on the subject which stops below the Supreme Court has been relatively light, and the constitutional law declared by the lower courts has played a less significant role than is the case in many other issues. Indeed, as we shall see, the Supreme Court itself has had less to say on the topic than might be hoped for. I shall try to indicate the main lines of scholarly debate, which is vast in quantity, if not always in insight; but it must be said that in constitutional law as a whole, and in this area in particular, the influence of scholarly opinion on the behavior of governments and courts has been less than may be observed in other fields of American law.
William B. Fisch, Emergency in the Constitutional Law of the United States,38 Am. J. Comp. L. Supp. 389 (1990)