A baby girl (defendant) was born to a Hispanic mother and a father who was Cherokee. The mother and father were unwed at the time of the birth, which occurred off reservation. While the mother was pregnant, the father relinquished parental rights to the child by text message to the mother. The baby was born and the mother placed the baby for adoption. The adoptive parents (plaintiffs), non-Indians, notified the father of the pending adoption. The father did not contest the adoption, but later sought custody in the adoption proceedings held before the family court in South Carolina. The court denied the adoption under the Indian Child Welfare Act (ICWA), 25 U.S.C. § 1901 et seq. Specifically, the court held that the father’s parental rights could not be involuntarily terminated under ICWA because the adoptive parents did not show that serious harm would come to the child by granting custody to the father. The South Carolina Supreme Court affirmed. The United States Supreme Court granted certiorari.