The University of Maryland granted lower tuition and fees to students with “in-state” status. Citizens and immigrant aliens may obtain in-state status if they or their parents are domiciled in Maryland. Nonimmigrant aliens may not obtain in-state status even if they meet the domicile requirements. Moreno and two other students (plaintiffs) all lived with nonimmigrant alien parents who were domiciled in Maryland and held a G-4 visa. G-4 visas are given to nonimmigrant aliens working for international organizations and their families. The three students sued the University for declaratory and injunctive relief, arguing that refusing to provide in-state status to children of domiciled G-4 aliens violated federal law and the due process, equal protection, and supremacy clauses of the United States Constitution. The Supreme Court granted certiorari on appeal.