After a four-decade legal battled waged by conservatives, the Indian Child Welfare Act (ICWA) is now in jeopardy of being overturned—a move that could lead to a marked increase in the number of Native children forced into the foster care and adoption systems.

Last Thursday (October 4), a federal judge in the United States District Court for the Northern District of Texas ruled on Brackeen v. Zinke. Reports The Texas Tribunte:

Backed by the state of Texas, Chad and Jennifer Brackeen—a non-Native American couple with two biological children—sued last October for the right to adopt a Native American toddler they had fostered for more than a year. A state court had denied their adoption petition; the federal law gives adoption placement preference to biological family members of Native American children, other members of the child’s tribe, or other Native American families. Texas Attorney General Ken Paxton sided with the Brackeens, arguing that the law unlawfully “elevates a child’s race over their best interest.”

Although the Brackeens settled their case, the states of Texas, Louisiana and Indiana continued with the lawsuit, arguing that ICWA hampered states’ rights to oversee their own child welfare proceedings. They also posited that it discriminated unconstitutionally on the basis of race.

The Indian Child Welfare Act was passed in 1978, when about one-third of Native American children were being taken from their families in state welfare cases. It was intended, writes The Tribune, “to preserve the integrity of Native American tribes.”

Conservatives have launched other legal challenges to ICWA since its passage 40 years ago, but last week’s decision marks the first time that a federal court ruled the law unconstitutional.

U.S. District Judge Reed O’Connor said in his decision that it was a “race based statute” that violates the Equal Protection Clause of the Constitution and the Tenth Amendment because it “commandeers” state courts to enforce a federal law.

Leaders from the Cherokee Nation, Morongo Band of Mission Indians, Oneida Nation and Quinault Indian Nation released a statement opposing the judge’s decision and calling it “wholly unjustified.” They will seek an immediate stay of the ruling and appeal O’Connor’s decision to the U.S. Court of Appeals for the Fifth Circuit, reports The Chronicle of Social Change.

“The Department of the Interior strongly opposes any diminishment of ICWA’s protections for Indian children, families and tribes,” Tara Mac Lean Sweeney, assistant secretary for Indian affairs at the agency, told The Chronicle. “The Department will continue to work with tribes and states to implement ICWA moving forward.”

In its statement, tribal leaders said, “These policies devastated tribal communities and we refuse to go back to those darker days. If ICWA is struck down in whole or in part, the victims will be our children and our families, Native children and Native families.”