The case is In re M.B. You can located the court’s opinion and the two appellate briefs on the Montana Supreme Court’s website here and searching for docket number 08-0443.
The question involved the adoptive placement rules of ICWA, in relation to children who were members of a state recognized tribe, the Little Shell Tribe of Chippewa Indians. The losing potential adoptive family did not raise the constitutional challenges until the appeal.
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