The level of judicial review for determining the constitutionality of a federal or state statute that does not implicate either a fundamental right or a suspect classification under the Due Process Clause and the Equal Protection Clause of the Constitution. When a court concludes that there is no fundamental liberty interest or suspect classification at stake, the law is presumed to be Constitutional unless it fails the rational basis test. Under the rational basis test, the courts will uphold a law if it is rationally related to a legitimate government purpose. The challenger of the constitutionality of the statute has the burden of proving that there is no conceivable legitimate purpose or that the law is not rationally related to it. This test is the most deferential of the three levels of review in due process or equal protection analysis (the other two levels being intermediate scrutiny and strict scrutiny), and it requires only a minimum level of judicial scrutiny. E.g., courts use the rational basis test when analyzing the constitutionality of statutes involving age discrimination, disability discrimination, or the Congressional regulation of aliens.