How does a moderate Republican vote on the confirmation of John R. Bolton, known for his bitter denunciations of the United Nations, as United States ambassador to the international body? Hearings by the Senate Foreign Relations Committee are under way, and a committee vote is expected this week. The moderates may well determine the outcome, either in the committee vote or later on the Senate floor.

Whether he will be confirmed remains a question, despite his testimony Monday pledging to “work with all” to build a stronger and more effective world body. Former Secretary of State Colin Powell’s name was noticeably missing from a last-minute roundup of five former secretaries supporting the Bolton nomination.

Critics had been placing their hopes on Sen. Lincoln Chafee, R-R.I., a member of the committee. But he said last Friday that he would vote to confirm Mr. Bolton unless some significant new anti-Bolton information turns up in the hearings. A “nay” vote by one of the 10 Republicans, assuming the eight Demo-crats stand firm against confirmation, would result in a 9-to-9 tie and block the issue from going to the full Senate.

Mr. Chafee faces the same difficult choice that confronts the half-dozen other moderate Republicans, including Maine’s Sens. Olympia Snowe and Susan Collins. They normally would support a nomination by a Republican president. Indeed, senators often assume that any president deserves to have his selections ratified.

Sixty-two former diplomats of both parties signed an anti-Bolton letter distributed to committee members. Among them were Arthur A. Hartman, ambassador to France and the Soviet Union under Presidents Jimmy Carter and Ronald Reagan, and assistant secretary of state for European affairs under President Richard M. Nixon. Bolton supporters came back with a statement by 66 former officials including former Defense Secretary Caspar Weinberger and former CIA Director James Woolsey.

Mr. Bolton is famous for having declared that if the U.N. Secretariat building in New York “lost 10 stories it wouldn’t make a bit of difference.” He also once told National Public Radio that the U.N. Security Council would need only one permanent member, the United States, “because that’s the real reflection of the distribution of power in the world.”

Mr. Chafee has tentatively resolved the question by concluding that the U.N. ambassador, while holding an important position, would not be making U.S. policy. He told The Providence Journal: “Ultimately, policy’s going to be made at the White House and the State Department.” He said Secretary of State Condoleezza Rice had told him that Mr. Bolton would be working for her. And he added, “She made it clear that we are going to be more respectful of these international institutions than maybe we were in the past.”

Dr. Rice thus suggested, as has President Bush, that the administration recognizes that it needs the support of the United Nations and nations like France and Germany in the campaign against world terrorism. Whether a blunt unilateralist like Mr. Bolton can inspire cooperation is an open question.

Other factors may influence the moderates’ votes on the Bolton question. They face other issues including Mr. Bush’s controversial effort to change Social Security, his determination to put a group of conservative judges on the appellate court bench, a likely move to kill or curtail the filibuster rule and the possibility of vacancies on the Supreme Court.

If they go along with their party on the Bolton confirmation, they may be conserving their ammunition for future disputes they consider more important.