Authorizes the President, if such provisions require it, to: (1) enter into a trade agreement with any foreign country or instrumentality for the purpose of granting new concessions as compensation in order to maintain the general level of reciprocal and mutually advantageous concessions; and (2) proclaim such modification or continuance of any existing duty or such continuance of existing duty-free or excise treatment as the President determines to be required or appropriate to carry out any such agreement.