On and after June 30, 1958 , Senate delegates to Conferences of the Interparliamentary Union shall be designated by the Presiding Officer of the Senate . Not less than two Senators so designated shall be members of the Committee on Foreign Relations. ( Pub. L. 85–474, title I , June 30, 1958 , 72 Stat. 246 ; Pub. L. 94–141, title II, § 204(c) , Nov. 29, 1975 , 89 Stat. 762 .) Editorial Notes Amendments 1975— Pub. L. 94–141 inserted at end “Not less than two Senators so designated shall be members of the Committee on Foreign Relations.”