19 U.S.C. § 2701
Authority to grant duty-free treatment
The President may proclaim duty-free treatment (or other preferential treatment) for all eligible articles from any beneficiary country in accordance with the provisions of this chapter.
( Pub. L. 98–67, title II, § 211 , Aug. 5, 1983 , 97 Stat. 384 ; Pub. L. 106–200, title II, § 211(e)(1)(A) , May 18, 2000 , 114 Stat. 287 .)