Chief Justice John Roberts noted that the child at the center of the case has less than 1 percent of Cherokee blood.
“Is it one drop of blood that triggers all these extraordinary rights?” he said.
Roberts asked whether the law would also to apply to a tribe that required no tribal blood for membership.
Justices also questioned attorneys about whether the best interests of the child were a factor in the case or in the federal law.
Justice Anthony M. Kennedy said the federal law displaces the determinations typically made by state courts about a child's best interests.
Arguing for the Obama administration, which is backing Brown and the Cherokee Nation in the case, Deputy Solicitor General Edwin Kneedler told justices that the federal law was meant to balance the competing interests of states and Indian tribes.
Kneedler said “nothing could be more at the core of tribal self-determination and tribal survival than the determination of tribal membership and the care about what happens to Indian children.”
What they're saying
Outside the Supreme Court before the arguments, Cherokee Nation Chief Bill John Baker prayed with Brown and tribal leaders and said, “If we fail, it will be a disaster for Indian country.”
In a brief interview, Baker said the federal law was approved when Indian children were being “shipped off” and removed from their heritage.
Inside the court, Blatt, the attorney for the adoptive couple, said the policy behind the law was “fantastic.”
“It was talking about Indian families who were being ripped away because of cultural biases and insensitivity,” she said.
“This case didn't involve cultural biases.”