26 U.S.C. § 7852: Other applicable rules

If any provision of this title, or the application thereof to any person or circumstances, is held invalid, the remainder of the title, and the application of such provision to other persons or circumstances, shall not be affected thereby. Any reference in any other law of the United States or in any Executive order to any provision of the Internal Revenue Code of 1939 shall, where not otherwise distinctly expressed or manifestly incompatible with the intent thereof, be deemed also to refer to the corresponding provision of this title. Except as otherwise distinctly expressed or manifestly intended, the same item (whether of income, deduction, credit, or otherwise) shall not be taken into account both in computing a tax under subtitle A of this title and a tax under chapter 1 or 2 of the Internal Revenue Code of 1939. For purposes of determining the relationship between a provision of a treaty and any law of the United States affecting revenue, neither the treaty nor the law shall have preferential status by reason of its being a treaty or law. No provision of this title (as in effect without regard to any amendment thereto enacted after August 16, 1954 ) shall apply in any case where its application would be contrary to any treaty obligation of the United States in effect on August 16, 1954 . The provisions of subsections (d)(2), (3), and (4), and (g) of section 552a of title 5 , United States Code, shall not be applied, directly or indirectly, to the determination of the existence or possible existence of liability (or the amount thereof) of any person for any tax, penalty, interest, fine, forfeiture, or other imposition or offense to which the provisions of this title apply.