North American Free Trade Agreement Implementation Act §201(a)(1)
(1993):31 “The President may proclaim—(A) such modifications or continuation of any duty, (B) such continuation of duty-free or excise treatment, or (C) such additional duties, as the President determines to be necessary or appropriate to carry out or apply [specified] articles ... of the Agreement.”
“Bipartisan Congressional Trade Priorities and Accountability Act of 2015
§103(a):35 “Whenever the President determines that one or more existing duties or other import restrictions of any foreign country or the United States are unduly burdening and restricting the foreign trade of the United States and that the purposes, policies, priorities, and objectives of this chapter will be promoted thereby, the President ... may ... proclaim—(i) such modification or continuance of any existing duty, (ii) such continuance of existing duty-free or excise treatment, or (iii) such additional duties, as the President determines to be required or appropriate to carry out any such trade agreement.... The President shall notify Congress of the President’s intention to enter into an agreement under this subsection.” This authority is subject to the following restrictions: “No proclamation may be made under paragraph (1) that—(A) reduces any rate of duty (other than a rate of duty that does not exceed 5 percent ad valorem on June 29, 2015) to a rate of duty which is less than 50 percent of the rate of such duty that applies on June 29, 2015; (B) reduces the rate of duty below that applicable”
“In Cornet Stores v. Morton, a case involving a challenge to a presidential proclamation that imposed a 10% surcharge duty on certain imported merchandise in light of a declared national emergency, the plaintiffs sought recovery of the import surcharges they had paid, relying on the jurisdictional provisions of the Trading with the Enemy Act of 1917.37 Both the district court and the U.S. Court of Appeals for the Ninth Circuit dismissed the matter, finding it fell within the exclusive jurisdiction of the former Court of Customs and Patent Appeals Court (Customs Court), which has since been replaced at the trial level by the U.S. Court of International Trade (CIT).”
“Cornet Stores v. Morton, 632 F.2d 96, 97 (9th Cir. 1980).”
In 1928, a similar challenge was brought in the Customs Court in J.W. Hampton, Jr., & Co. v. United States. In Hampton, an importer challenged an increase in duties on certain imported goods as a result of a presidential proclamation issued under Section 315 of the Tariff Act of 1922, which provides:
[W]henever the President, upon investigation of the differences in costs of production of articles wholly or in part the growth or product of the United States and of like or similar articles wholly or in part the growth or product of competing foreign countries, shall find it thereby shown that the duties fixed in this act do not equalize the said differences in costs of production in the United States and the principal competing country he shall, by such investigation, ascertain said differences and determine and proclaim the changes in classifications or increases or decreases in any rate of duty provided in this act shown by said ascertained differences in such costs of production necessary to equalize the same.”
https://www.congress.gov/crs-product/R44707
Thank you for time and effort posting these for greater understanding. This is a somewhat complex issue that avoids most people’s radar.