The Interior Department in Washington. (Mark Wilson/Getty Images)

Ken Paxton is the attorney general of Texas.

In June 2016, Texas couple Chad and Jennifer Brackeen took a 10-month-old Native American foster child into their home. The boy, referred to as A.L.M. in court documents, had been the victim of parental neglect and drug abuse from birth. He soon became part of the Brackeens’ family. After caring for him for more than a year, the Brackeens — with the support of A.L.M.’s biological parents and the court-appointed guardian overseeing his welfare — decided to adopt him. Little did they know that, instead of encouraging the adoption, an obscure federal law would force state child-welfare officials to try to tear the boy from the family.

Government officials planned to place A.L.M. with a couple in New Mexico whom he barely knew and with whom he had no family ties. Virtually everyone interested in the child’s welfare supported his adoption by the Brackeens and opposed his forced move to New Mexico. But officials prepared to go ahead with the separation anyway.

Why did A.L.M.’s obvious best interest count for so little?

In 1978, Congress enacted the Indian Child Welfare Act. It was intended to address concerns that public and private entities were too willing to break up Native American families unnecessarily.

But the law, and its implementation over the years, went too far. In practice, the ICWA compels states to disregard the ordinary approach of determining a child’s best interest and to treat Native American foster children differently based on nothing more than their race. The law gives Indian tribes a trump card to play in any state child-welfare proceeding, allowing them to dictate outcomes whenever a child is or even could be a member of a tribe. If no biological family members can be found, the law requires state courts and agencies to make a priority of adoption by other ethnically Native American families.

This racial preference prevails in both foster care and adoption proceedings, even when the child has no tribal citizenship, no cultural connection to a given tribe and no interest in leaving his or her established foster family. The presumption in favor of Native Americans supersedes the best interest of the child, which — it should be obvious — lies in finding a caring, stable family regardless of race.

Native American children, strictly because of their race, thus can be kept apart from foster families eager to adopt them. If federal law treated any other class of people this way, it would be roundly condemned, and rightly so. According to the Department of Health and Human Services, 10,529 American Indian/Alaska Native children were in foster care in fiscal 2017.

Some claim that the ICWA relies on a political designation, rather than a racial one, because a tribe is a political entity. But no political or cultural link to a tribe must exist for the Indian Child Welfare Act to apply to a given child. Tribal eligibility — determined in virtually every case by genetic ancestry — is sufficient. The idea that the ICWA relies on a political designation rather than a racial one is further undermined by the fact that if no family from the child’s tribe volunteers to adopt, any Native American from any tribe, anywhere, takes automatic precedence over a non-Native American couple. This requirement relies on racist and reductionist assumptions about the supposed interchangeability of drastically different tribal cultures.

Disturbingly, even if an adoption by a non-Native American family goes through, the ICWA allows a tribal government to petition a state court to take the child away up to two years after becoming a member of the family.

In the Brackeens’ case, the Native American couple eventually withdrew its claim, allowing the family to stay together. But that was a happy coincidence for the rule of law and for the family ’s the exception; without it, the ICWA would have required their separation.

Along with the Brackeens, I joined the attorneys general of Louisiana and Indiana in suing to strike down this discriminatory law. A federal court in October sided with us. Among other findings, the judge held that the ICWA discriminates based on race in violation of equal protection and commandeers state governments in violation of the 10th Amendment. A basic principle of federalism holds that federal law cannot commandeer state governments; doing so is even less justifiable when the federal requirement is itself illegal and discriminatory. The defendants, including the Interior Department and several tribes, are appealing the ruling.

Knowing the many hoops they would have to jump through even to get in the door — as well as the looming threat of separation if they somehow manage to complete the adoption of a Native American child — many couples who want to adopt simply turn elsewhere. The tragic result is that countless Native American children are prevented from joining a family committed to their well-being.

Compensating for injustice against Native American peoples in the past cannot justify mistreating their children in the present.