The four major suspect classifications that receive strict scrutiny before the Supreme Court are race, national origin, alienage and religion, according to the UMKC School of Law. Suspect classification is defined as a characteristic applied to laws that denotes illegal discrimination because the classification of certain criminals is suspect in court cases, according to USLegal. The most obvious suspect classification that goes before the Supreme Court is race.
USLegal explains that the Supreme Court has no definitive list of suspect classifications, but the highest court reviews cases involving people who have an inherent trait, have a trait that is highly visible and have been disadvantaged or have lacked representation in a historical context. As such, racial and ethnic classifications have received the highest scrutiny by the Supreme Court.
In order for a suspect classification case to be reviewed by the Supreme Court, the government must show the classification has a "compelling state interest" to serve the people. UMKC reveals the most famous case involving suspect classification occurred in the 1938 review of Carolene Products v. United States, in which a footnote to the court's decision urged future justices to exact "judicial scrutiny" with respect to the Fourteenth Amendment. Loving v. Virginia was a unanimous decision in 1967 that struck down Virginia's law banning interracial marriages. Skinner v. Oklahoma was a 1942 case that invalidated Oklahoma's law regarding sterilization of suspects convicted of three felonies involving moral turpitude.