In general— The authorities conferred upon the President by section 5(b) of the Trading With the Enemy Act (
50 U.S.C. 4305(b)), which were being exercised with respect to Cuba on July 1, 1977, as a result of a national emergency declared by the President before that date, and are being exercised on the day before the date of the enactment of this Act, may not be relied upon on or after such date of enactment to continue the imposition of direct restrictions on trade with Cuba.