At the intersection of immigration and equal protection lies a judicial vortex. This area of law is a twilight zone of sorts, where established constitutional principles do not follow their regular paths.1 The Equal Protection Clause of the Fourteenth Amendment applies to all who fall within the jurisdiction of a state, including noncitizens.2 Generally, the same equal protection restrictions placed on state laws through the Fourteenth Amendment also restrict federal law through the Due Process Clause of the Fifth Amendment.3 But the Constitution gives Congress exclusive power over immigration, which the Supreme Court has interpreted as a plenary power that is not subject to traditional judicial review.4 Thus, discriminatory laws that would incur rigorous judicial review if passed by state legislatures are given, at most, a rational basis review if passed by Congress.5
Furthermore, laws passed by the states, whether discriminatory or not, are invalid under the Supremacy Clause if they impose upon Congress's exclusive authority to regulate immigration. If Congress expressly grants certain privileges to noncitizens, state laws that revoke those privileges will be preempted. The Supremacy Clause, therefore, is an unwitting companion to the Equal Protection Clause in striking down discriminatory state laws.
Courts handling cases of state discrimination against noncitizens typically review the offending state law under both the Equal Protection Clause and the Supremacy Clause. But the courts either evaluate the two clauses separately, as alternative holdings, or they blur the line between the two clauses by using Supremacy Clause justifications to invalidate state laws under the Equal Protection Clause. More disconcerting, however, is that courts differ on the proper equal protection review standard to apply to one particular class of noncitizen: nonimmigrants.
How equal protection applies to discriminatory state laws depends on the immigration status of the noncitizen who protests the law - some are given more protection than others. There are three broad classes of noncitizens in the United States: permanent residents, nonimmigrants, and illegal immigrants. Permanent residents are most similar to citizens.6 They are entitled to live in the United States permanently.7 Nonimmigrants enter the country for a variety of reasons and under a variety of conditions, but are generally only here temporarily.8 Illegal immigrants, as the title suggests, are noncitizens who enter or stay in the United States without permission.
State laws have discriminated against all three of these classes, but the standard of equal protection review is not always clear. The Supreme Court has held that state laws that discriminate based on "alienage" are subject to strict scrutiny review under the Equal Protection Clause. But the Court has not defined "alienage" and has only applied strict scrutiny when permanent residents challenge discriminatory state laws. With one specific exception, the Court has stated that laws discriminating against illegal immigrants are only subject to a rational basis review.
Nonimmigrants, however, do not enjoy a well-defined standard of review. The Supreme Court has avoided the issue, leaving a legal gap that has led to disagreement among lower courts. Some courts argue that laws discriminating against nonimmigrants should only be given a rational basis review because the Supreme Court has applied strict scrutiny only when permanent residents protest discriminatory laws. Other courts, however, argue that these discriminatory laws should be reviewed using strict scrutiny because "alienage" discrimination includes all aliens and general language used by the Supreme Court does not limit that interpretation.
This debate, however, frequently ignores the rationale for giving any class heightened equal protection scrutiny. Supreme Court cases have identified characteristics of discrete classes that justify heightened scrutiny, but lower court cases discussing nonimmigrants as a class have brushed over these characteristics. …