Last year Sen. George Voinovich, R-Ohio, in the Senate Foreign Relations Committee opposed Bolton's confirmation as U.S. Ambassador to the United Nations, leading to President Bush making a recess appointment. According to the WP:
the senator has had a change of heart, saying last week that he would not block Bolton's nomination this year because of an urgent need to ease tensions in the Middle East.The GOP-controlled Senate Committee has scheduled a hearing for Thursday on Bolton's nomination. If confirmed by the Senate, Bolton would be expected to serve as UN Ambassador through the rest of the Bush Administration. It seems likely that the nomination will go forward to the full Senate, and that Democrats will oppose it in the Committee and on the floor of the Senate.
Since UNESCO is part of the United Nations family of organizations, the U.S. Ambassador to the United Nations has significant influence on U.S. policy towards UNESCO.