"In 1938, seven Justices heard a constitutional challenge to a federal ban on shipping adulterated milk in interstate commerce. Without economic substantive due process, the ban clearly invaded no constitutional right. See United States v. Carolene Products Co., 304 U. S. 144 –153 (1938). Within Justice Stone’s opinion for the Court, however, was a footnote that just three other Justices joined—the famous Carolene Products Footnote 4. See ibid., n. 4; Lusky, Footnote Redux: A Carolene Products Reminiscence, 82 Colum. L. Rev. 1093, 1097 (1982). The footnote’s first paragraph suggested that the presumption of constitutionality that ordinarily attaches to legislation might be “narrower . . . when legislation appears on its face to be within a specific prohibition of the Constitution.” 304 U. S., at 152–153, n. 4. Its second paragraph appeared to question “whether legislation which restricts those political processes, which can ordinarily be expected to bring about repeal of undesirable legislation, is to be subjected to more exacting judicial scrutiny under the general prohibitions of the [14th] Amendment than are most other types of legislation.” Ibid. And its third and most familiar paragraph raised the question “whether 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.” Ibid. Though the footnote was pure dicta, the Court seized upon it to justify its special treatment of certain personal liberties like the First Amendment and the right against discrimination on the basis of race—but also rights not enumerated in the Constitution.[2] As the Court identified which rights deserved special protection, it developed the tiers of scrutiny as part of its equal protection (and, later, due process) jurisprudence as a way to demand extra justifications for encroachments on these rights. See Fallon, 54 UCLA L. Rev., at 1270–1273, 1281–1285. And, having created a new category of fundamental rights, the Court loosened the reins to recognize even putative rights like abortion, see Roe, 410 U. S., at 162–164, which hardly implicate “discrete and insular minorities.”"