Passed by the United States Senate in 1866, the Fourteenth Amendment to the Constitution granted citizenship to "all persons born or naturalized in the United States." Importantly, this included people who were formerly enslaved. Today, the Fourteenth Amendment performs the essential function of ensuring that laws in the United States protect and preserve everyone's rights equally. This is known as the equal protection doctrine.
"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."
United States Library of Congress, The Constitution of the United States of America: Analysis and Interpretation
Government classifications that adversely affect a person's fundamental liberties or interests must be justified by a showing of compelling government interest, as well as proof that the distinction is required to further that purpose. This is known as the "strict scrutiny" test. The effect of applying the test, as in the other branch of active review, is to deny to legislative judgments the deference usually accorded them and to dispense with the general presumption of constitutionality usually given state classifications.1
It is thought2 that the fundamental right theory had its origins in Skinner v. Oklahoma ex rel. Williamson,3 in which the Court subjected to strict scrutiny a state statute providing for compulsory sterilization of habitual criminals, such scrutiny being thought necessary because the law affected one of the basic civil rights. In the apportionment decisions, Chief Justice Warren observed that, since the right to exercise the franchise in a free and unimpaired manner is preservative of other basic civil and political rights, any alleged infringement of the right of citizens to vote must be carefully and meticulously scrutinized.4
A stiffening of the traditional test could be noted in the opinion of the Court striking down certain restrictions on voting eligibility5 and the phrase compelling state interest was used several times in Justice Brennan's opinion in Shapiro v. Thompson.6 Thereafter, the phrase was used in several voting cases in which restrictions were voided, and the doctrine was asserted in other cases.7
Although no opinion of the Court attempted to delineate the process by which certain fundamental rights were differentiated from others,8 it was evident from the cases that the right to vote,9 the right of interstate travel,10 the right to be free of wealth distinctions in the criminal process,11 and the right of procreation12 were at least some of those interests that triggered active review when de jure or de facto official distinctions were made with respect to them.
In San Antonio School District v. Rodriguez,13 the Court also sought to rationalize and restrict this branch of active review. That case involved both a claim that de facto wealth classifications should be suspect and a claim that education was a fundamental interest, such that providing less of it to people because they were poor triggered a compelling state interest standard. The Court readily agreed that education was an important value in our society, but:
"[T]he importance of a service performed by the State does not determine whether it must be regarded as fundamental for purposes of examination under the Equal Protection Clause. . . . [T]he answer lies in assessing whether there is a right to education explicitly or implicitly guaranteed by the Constitution."14
A right to education is not expressly protected by the Constitution, continued the Court, and it was unwilling to find an implied right because of its undoubted importance.
But just as Rodriguez did not ultimately prevent the Court's adoption of a three-tier or sliding-tier standard of review, Justice Powell's admonition that only interests expressly or impliedly protected by the Constitution should be considered fundamental did not prevent the expansion of the list of such interests.
The difficulty was that Court decisions on the right to vote, the right to travel, the right to procreate, as well as other rights, premise the constitutional violation to be of the Equal Protection Clause, which does not itself guarantee the right but prevents the differential governmental treatment of those attempting to exercise the right.15 Thus, state limitation on the entry into marriage was soon viewed as an infringement on a fundamental right that required a compelling justification.16
Although denials of public funding of abortions were held to implicate no fundamental interest,17 other denials of public assistance because of alienage, sex, or whether a person was born out of wedlock have been deemed to be governed by the same standard of review as affirmative harms imposed on those grounds.18 And, in Plyler v. Doe,19 the complete denial of education to the children of unlawfully present aliens was found subject to intermediate scrutiny and invalidated.
An open question after Obergefell v. Hodges, the 2015 case finding the right to same-sex marriage is protected by the Constitution, is the extent to which the Court is reconceptualizing equal protection analysis.20 In Obergefell, the Court concluded that state laws that distinguished between marriages between same- and opposite-sex married couples violated the Equal Protection Clause.21
However, in lieu of more traditional equal protection analysis, the Obergefell Court did not identify whether the base classification made by the challenged state marriage laws was suspect. Nor did the Obergefell Court engage in a balancing test to determine whether the purpose of the state classification was tailored to or fit the contours of the classification. Instead, the Court merely declared that state laws prohibiting same-sex marriage abridge[d] central precepts of equality.22
It remains to be seen whether Obergefell signals a new direction for the Court's equal protection jurisprudence or is merely an anomaly that indicates the fluctuating nature of active review, as the doctrine has been subject to shifting majorities and varying degrees of concern about judicial activism and judicial restraint. Nonetheless, the sliding scale of review underlies many of the Court's most recent equal protection cases, even if the jurisprudence and its doctrinal basis have not been fully elucidated or consistently endorsed by the Court.