The U.S. Supreme Court on Thursday rejected a challenge to a federal law aimed at keeping Native American children within the foster care system in Native American homes.

The Supreme Court in a 7-2 decision upheld the 1978 Indian Child Welfare Act, which established federal minimum standards for the removal of Native American children from their homes. The law also prioritized placing children into homes of extended family members and other tribal homes — places that could reflect the values of Native American culture.

ICWA was enacted in an effort to rectify historical wrongs caused by a centuries-long campaign by the federal government of forcibly removing Native children from their homes and placing them in boarding schools and white adoptive families. The mission was to assimilate Native children into the white American mainstream.

Before ICWA was adopted, between 25% to 35% of all Native American children were being taken from their homes and placed with adoptive families, foster care or boarding schools.

The case, Brackeen v. Haaland, centered around a white Texas couple, Chad and Jennifer Brackeen, who argued that ICWA discriminates against non-Native families because of their race. ICWA proponents argued that tribal citizenship is a political, not racial, category.

Justice Amy Coney Barrett wrote the majority opinion, joined by six other justices. Justices Clarence Thomas and Samuel Alito dissented.

The Brackeens challenged ICWA after a long legal battle with the Navajo Nation to adopt a Native child. The couple eventually adopted the child and are now trying to adopt the boy’s half-sister, who has lived with them since infancy. The Navajo Nation has opposed that adoption.

The Brackeens, who were joined by other families and Texas, Indiana and Louisiana, had argued that it was unconstitutional for the federal government to racially discriminate against non-Native adoptive families. The plaintiffs also argued that Congress didn’t have the authority to pass ICWA, as family custody disputes are handled by states. The Supreme Court rejected their arguments.

“The issues are complicated,” Barrett wrote. “But the bottom line is that we reject all of the petitioners’ challenges to the statute, some on the merits and others for lack of standing.”

Alito in his dissent said criticized ICWA, saying the federal law has often resulted in custody cases omitting what is in a child’s best interest.

“Decisions about child custody, foster care, and adoption are core state functions. The paramount concern in these cases has long been the ‘best interests’ of the children involved,” Alito wrote. “But in many cases, provisions of the (ICWA) compel actions that conflict with this fundamental state policy, subordinating what family-court judges — and often biological parents — determine to be in the best interest of a child to what Congress believed is in the best interest of a tribe.”

Tribal leaders on Thursday praised the Supreme Court’s decision, saying it was a “major victory for Native tribes, children, and the future of our culture and heritage.”

“We hope this decision will lay to rest the political attacks aimed at diminishing tribal sovereignty and creating instability throughout Indian law that have persisted for too long,” said leaders of the Cherokee Nation, Morongo Band of Mission Indians, Oneida Nation and Quinault Indian Nation, in a statement.

Justice Neil Gorsuch in a concurring opinion joined by Justices Sonia Sotomayor and Ketanji Brown Jackson said he was “pleased to join the Court’s opinion in full,” adding that he wanted to note the historical significance of the opinion.

“The Indian Child Welfare Act did not emerge from a vacuum. It came as a direct response to the mass removal of Indian children from their families during the 1950s, 1960s, and 1970s by state officials and private parties,” Gorsuch wrote.”In all its many forms, the dissolution of the Indian family has had devastating effects on children and parents alike. It has also presented an existential threat to the continued vitality of Tribes — something many federal and state officials over the years saw as a feature, not as a flaw.”

Native rights proponents have argued that the Brackeen case was an attack on tribal sovereignty, and reporting from Rebecca Nagle, host of the podcast “This Land,” found that the lawyers behind the Brackeen case were backed by right-wing interest groups who have filed other cases challenging tribal sovereignty.

In a statement, U.S Secretary of the Interior Deb Haaland, the first Native American to serve in a president’s Cabinet, praised the Supreme Court’s decision.

“For nearly two centuries, federal policies promoted the forced removal of Indian children from their families and communities through boarding schools, foster care and adoption,” Haaland said. “Those policies were a targeted attack on the existence of Tribes, and they inflicted trauma on children, families and communities that people continue to feel today.”