UMKC.edu ~ The Right to MarryThe first state marriage law to be invalidated was Virginia's miscegenation law in Loving v Virginia (1967). Mildred Jeter, a black woman, and Richard Loving, a white man, had been found guilty of violating Virginia's ban on interracial marriages and ordered to leave the state. The Court found Virginia's law to violate the Equal Protection Clause because it invidiously classified on the basis of race, but it also indicated the law would violate the Due Process Clause as an undue interference with 'the fundamental freedom" of marriage.
In Zablocki v Redhail (1978), the Court struck down a Wisconsin law that required persons under obligations to pay support for the children of previous relationships to obtain permission of a court to marry. The statute required such individuals to prove that they were in compliance with support orders and that marriage would not threaten the financial security of their previous offspring. The Court reasoned that marriage was "a fundamental right" triggering "rigorous scutiny" of Wisconsin's justifications under the Equal Protection Clause.
In Turner v Safley (1987), the Court refused to apply strict scutiny to a Missouri prison regulation prohibiting inmates from marrying, absent a compelling reason. Instead, the Court found the regulation failed to meet even a lowered standard of "reasonableness" that it said it would apply in evaluating the constitutionality of prison regulations.
Might want to look again.