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President Bush's nomination of John Bolton (search) as the U.S. ambassador to the United Nations (search) has stirred deeply the feelings in Washington. Senate Republicans are confident they will confirm him, but liberal groups are using Bolton's own words against him in a last-ditch TV campaign.

Bolton, the former undersecretary at the State Department for arms control and international security, faces a sharply divided Senate with nearly all 44 Democrats opposed to his nomination.

"Over the past 30 years, John Bolton has advertised himself as an unadulterated nationalist and opponent of multilateralism. He's not a healthy skeptic of the United Nations but widely known as a committed destructive opponent, an ideological lone ranger," said Ambassador Jonathan Dean (search), a senior U.S. arms control negotiator in the Carter administration who penned a letter in opposition to Bolton signed by 62 former diplomats and U.S. officials.

Two liberal, pro-U.N. groups produced a low-budget ad to illustrate what they say is Bolton's hostility to the world body. The ad quotes a 1990s speech by Bolton in which he said, "The United States makes the U.N. work when it wants it to work, and if you don't like that, I'm sorry, but that is the fact."

"Is this the man we want at the U.N.? America doesn't need a loose cannon, it needs a problem-solver ... John Bolton, wrong ideas, wrong message and the wrong man for the job," says the ad produced by Citizens for Global Solutions.

The ad is designed to increase political pressure on Republican Sens. Lincoln Chafee (search) of Rhode Island and Chuck Hagel (search) of Nebraska. The ad will run in their states. Hagel already has endorsed Bolton and Chafee aides told FOX News that the senator is "inclined to support Bolton."

Senate Republicans say they have the votes to confirm Bolton.

"Presently, the U.N. is in some disrepute. Their credibility is on the line and somebody like John Bolton, in fact, John Bolton is the perfect person at this time to bring some scrutiny and accountability to the United Nations, which will help its credibility as well," said Virginia Republican Sen. George Allen.

Aides to Senate Minority Leader Harry Reid say Hagel's and Chafee's support for Bolton made it tougher for Democrats to use a filibuster to block Bolton's nomination. But Reid hasn't taken the option off the table, his aides told FOX News.

Nonetheless, Beltway conservatives are taking no chances — more than 70 former diplomats and officials signed a letter to Senate Foreign Relations Committee Chairman Richard Lugar praising Bolton's "impressive intellect and robust diplomatic skills."

On Tuesday, five Republican former secretaries of state also penned a letter to Lugar supporting Bolton.

"We must have an ambassador in place whose knowledge, experience, dedication and drive will be vital to protecting the American interest in an effective, forward-looking United Nations," wrote former Secretaries James A. Baker III, Lawrence Eagleburger, Alexander Haig, Henry Kissinger and George Shultz. Former U.N. Ambassador Jeanne Kirkpatrick and five other retired senior U.S. officials also signed the letter.

"A person like John Bolton ... is not just going to espouse sweet diplomatic platitudes but will call things as he sees them and sees where the reforms need to be made," Allen said.

While Republicans may have the votes, Democrats say they have the questions to make Bolton's confirmation hearing as miserable as possible. Lugar has set aside Thursday for a hearing on Bolton, reserving Friday if necessary to give Bolton time to rebut his critics.

Click in the box near the top of the story to watch a report by FOX News' Major Garrett.