Zablocki v. Redhail, 434 U.S. 374 (1978), was a U.S. Supreme Court decision that held that Wisconsin Statutes ยงยง 245.10 (1), (4), (5) (1973) violated the Fourteenth Amendment equal protection clause. Section 245.10 required noncustodial parents who were Wisconsin residents attempting to marry inside or outside of Wisconsin to seek a court order prior to receiving a marriage license. In order to receive such a court order, the noncustodial parent could not be in arrears on his or her child support, and the court had to believe that the child(ren) would not become dependent on the State.
Read more about Zablocki V. Redhail: History, Opinion of The Court, Rehnquist's Dissent