19 U.S.C. § 2137 — Reservation of articles for national security or other reasons

(a) National security considerations. The President may not proclaim a reduction or elimination of a duty^* or other import restriction^* under this chapter if he determines that the reduction or elimination would threaten to impair national security.

(b) Action under other laws. While an action concerning an article is in effect under section 2253, section 1862, or section 1981, the President must reserve that article from negotiations under this subchapter, and from action under section 2132(c), that would reduce or eliminate—
(A) a duty on the article;
(B) an import restriction imposed under that section; or
(C) another import restriction whose removal would likely weaken the effect of the import restrictions described in subparagraph (B).
The President must also reserve any other article he decides should be reserved, considering available information and advice under or about sections 2151, 2152, and 2153 when applicable.