In U.S. constitutional law, rational basis review is the normal standard of review that courts apply when considering constitutional questions, including due process or equal protection questions under the Fifth Amendment or Fourteenth Amendment. Courts applying rational basis review seek to determine whether a law is "rationally related" to a "legitimate" government interest, whether real or hypothetical.[1] The higher levels of scrutiny are intermediate scrutiny and strict scrutiny.[2] Heightened scrutiny is applied where a suspect or quasi-suspect classification is involved, or a fundamental right is implicated.[1] In U.S. Supreme Court jurisprudence, the nature of the interest at issue determines the level of scrutiny applied by appellate courts. When courts engage in rational basis review, only the most egregious enactments, those not rationally related to a legitimate government interest, are overturned.[3][4][5]
Rational basis review tests whether the government's actions are "rationally related" to a "legitimate" government interest.[6][7] The Supreme Court has never set forth standards for determining what constitutes a legitimate government interest.[8] Under rational basis review, it is "entirely irrelevant" what end the government is actually seeking and statutes can be based on "rational speculation unsupported by evidence or empirical data".[9] Rather, if the court can merely hypothesize a "legitimate" interest served by the challenged action, it will withstand rational basis review.[10] Judges following the Supreme Court's instructions understand themselves to be "obligated to seek out other conceivable reasons for validating" challenged laws if the government is unable to justify its own policies.[11]