Fourteenth Amendment, Section 1:
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
Toward the end of the Warren Court, there emerged a trend to treat classifications on the basis of nationality or alienage as suspect, 1 to accord sex classifications a somewhat heightened traditional review while hinting that a higher standard might be appropriate if such classifications passed lenient review, 2 and to decide cases concerning statutory and administrative treatments of children born out of wedlock inconsistently. 3 Language in a number of opinions appeared to suggest that poverty was a suspect condition, so that treating the poor adversely might call for heightened equal protection review. 4
However, in a major evaluation of equal protection analysis early in this period, the Court reaffirmed a two-tier approach, determining that where the interests involved that did not occasion strict scrutiny, the Court would decide the case on minimum rationality standards. Justice Powell, writing for the Court in San Antonio School Dist. v. Rodriguez, 5 decisively rejected the contention that a de facto wealth classification, with an adverse impact on the poor, was either a suspect classification or merited some scrutiny other than the traditional basis, 6 a holding that has several times been strongly reaffirmed by the Court. 7 But the Court’s rejection of some form of intermediate scrutiny did not long survive.
Without extended consideration of the issue of standards, the Court more recently adopted an intermediate level of scrutiny, perhaps one encompassing several degrees of intermediate scrutiny. Thus, gender classifications must, in order to withstand constitutional challenge,
serve important governmental objectives and must be substantially related to achievement of those objectives. 8 And classifications that disadvantage persons born out of wedlock are subject to a similar though less exacting scrutiny of purpose and fit. 9 This period also saw a withdrawal of the Court from the principle that alienage is always a suspect classification, so that some discriminations against aliens based on the nature of the political order, rather than economics or social interests, need pass only the lenient review standard. 10
The Court has so far resisted further expansion of classifications that must be justified by a standard more stringent than rational basis. For example, the Court has held that age classifications are neither suspect nor entitled to intermediate scrutiny. 11 Although the Court resists the creation of new suspect or
quasi-suspect classifications, it may still, on occasion, apply the Royster Guano rather than the Lindsley standard of rationality. 12