The Commissioner of Internal Revenue, a federal agency, applied federal income tax to the on-reservation income of an Indian despite a constitutional provision that Indians Not [be] Taxed and in the absence of an Act of Congress clearly authorizing the tax.

The question presented is: Did the Court of Appeals err in upholding federal income tax on an individual Indian's self-employment income earned on his Tribe's reservation without Treaty, constitutional, or congressional expressly stated authorization for that taxation?

Did the Court of Appeals err in upholding federal income tax on an individual Indian's self-employment income earned on his Tribe's reservation without Treaty, constitutional, or congressional expressly stated authorization for that taxation?