The act applies only to an "Indian child," which is defined as "any unmarried person who is under age eighteen and is either (a) a member of an Indian tribe or (b) is eligible for membership in an Indian tribe and is the biological child of a member of an Indian tribe." Id. The federal Act was adopted in 1978 to address the "...alarmingly high percentage of Indian families [...] broken up by the removal, often unwarranted, of their children from them by nontribal public and private agencies and [...the] alarmingly high percentage of such children [...] placed in non-Indian foster and adoptive homes and institutions." 25 USC 1901(4).
If child custody proceedings involve an Indian child, or there is any indication that the child might meet either of the definitions of an Indian child, the rather extensive and detailed provisions of ICWA must be followed. This is key, because failure to follow certain provisions of ICWA may lead to reversal. In at least one United States Supreme Court case, Mississippi Band of Choctaw Indians v. Holyfield, 490 US 30 (1989), reversal meant that termination of parental rights and an adoption were in essence undone. Therefore, even if social workers, attorneys, parents, caregivers, the court, and other stakeholders are unfamiliar with the exact requirements of ICWA, it is essential that they at a minimum be able to recognize when and if ICWA applies.