For the purposes of this subchapter:

(1) The term "strategic and critical materials" means materials that (A) would be needed to supply the military, industrial, and essential civilian needs of the United States during a national emergency, and (B) are not found or produced in the United States in sufficient quantities to meet such need.

(2) The term "national emergency" means a general declaration of emergency with respect to the national defense made by the President or by the Congress.