Here is the opening brief in United States v. Jim (10th Cir.):

Jim Opening Brief

appellee-brief-1.pdf

reply-5.pdf

An excerpt:

There is reason to believe that the Supreme Court may be open to revisiting its holding in Antelope, and may soon have the opportunity to cast doubt on the continued vitality of Antelope. In a case unrelated to the Major Crimes Act, the Court struck down a statute that created a voting qualification that, it said, used native Hawai’ian ancestry as “a proxy for race.” Rice v. Cayetano, 528 U.S. 495, 519-20 (2000). Most recently, and after Mr. Jim’s sentencing hearing in this case, a federal district court struck down the Indian Child Welfare Act as unconstitutional because of the race-based restrictions that it places on foster care and adoption. See Brackeen v. Zinke, 338 F. Supp. 3d 514 (N.D. Tex. 2018). The court focused on the fact that the statute based Indian classification on blood, and did not “rely on actual tribal membership,” to distinguish Mancari. Id. at 533. As is clear from the appellate docket in the Fifth Circuit, Case No. 18-11479, the district court’s ruling has generated significant interest among law makers, tribal governments, non-profits, and Indian law scholars, all of whom have submitted amicus briefs. The Fifth Circuit heard oral arguments in the case on March 13 of this year. See Docket entry of March 13, 2019, Brackeen v. Barnhard, app. pending, Case No. 18-11479 (5th Cir.); Andrew Westney, “Texas AG Lauds Child Welfare Ruling, but Tribes Cry Foul,” Law360 (March 4, 2019), at https://www.law360.com/articles/1134688. Ultimately, if the district court’s decision is preserved by the Supreme Court, that would significantly undermine Antelope and open the Major Crimes Act to challenge on these grounds.