The President shall designate from time to time a representative of the United States and not to exceed two alternates to attend a specified session or specified sessions of the general council of the Organization. Whenever the United States is elected to membership on the executive committee, the President shall designate from time to time, either from among the aforesaid representative and alternates or otherwise, a representative of the United States and not to exceed one alternate to attend sessions of the executive committee. Such representative or representatives shall each be entitled to receive compensation at a rate not to exceed $12,000 per annum, and any such alternate shall be entitled to receive compensation at a rate not to exceed $10,000 per annum, for such period or periods as the President may specify, except that no Member of the Senate or House of Representatives or officer of the United States who is designated as such a representative shall be entitled to receive such compensation.