19 U.S.C. § 1881: Normal trade relations

Except as otherwise provided in this subchapter, in section 1351 of this title, or in section 401(a) of the Tariff Classification Act of 1962, any duty or other import restriction or duty-free treatment proclaimed in carrying out any trade agreement under this subchapter or section 1351 of this title shall apply to products of all foreign countries, whether imported directly or indirectly.