In United States v. Carolene Products Co.,' Justice Stone suggested by indirection that there "may be narrower scope for operation of the presumption of constitutionality" when courts are called upon to determine the validity "of statutes directed at particular religious . . . or national . . . or racial minorities."2 In such cases, he explained, "prejudice against discrete and insular minorities may be a special condition, which tends seriously to curtail the operation of those political processes ordinarily to be relied upon to protect minorities, and which may call for a correspondingly more searching judicial inquiry."3 Forty years later, that cautious suggestion has ripened into an attitude. The fact that legislation bears heavily upon the interests of a minority has come to be widely regarded as a reason for subjecting it to closer judicial scrutiny than other legislation whose constitutionality is challenged and perhaps as creating a presumption of its invalidity. Yet, exactly what is meant by these conclusions is, even now, far from certain. With the passing of time, moreover, the boundaries that circumscribed Stone's suggestion have become blurred. His reference to "discrete and insular minorities" has been