Updated

President Bush's pick to be the U.S. ambassador to the United Nations pledged Monday to "work with all" to build a stronger and more effective world body, which he said has sometimes gone "off track."

The Bush administration is committed to the success of the United Nations, John R. Bolton (search) said during his confirmation hearing before the Senate Foreign Relations Committee. He told lawmakers that "we view the U.N. as an important component of our democracy."

Bolton, currently undersecretary for arms control and international security at the State Department, has been one of the Republicans' strongest conservative voices on foreign affairs issues. Critics say the 56-year-old official, who has served the last three Republican presidents and is a strong advocate of overhauling the United Nations, is considered too antagonistic and adversarial to the world body to represent the United States.

Democratic Sen. Joseph Biden (search) of Delaware, the ranking member of the committee, grilled Bolton about a variety of issues, most specifically on reports alleging that Bolton pressured intelligence agents on pre-Iraq invasion weapons of mass destruction (search) reports.

The senator said Monday that Bolton's past criticisms of the United Nations "do not advance U.S. interests."

Biden said that while the president was entitled to "significant deference" to his nominations, he cited his own history of voting against nominees "who I believe were hostile to the mission to which they were assigned."

"I'm surprised the nominee wants the job he's been nominated for, given the many negative things he's had to say about the U.N.," Biden added.

Sen. George Allen (search), R-Va., however, called Bolton "the absolute perfect person for the job."

Bolton was asked about the impact on American standing overseas of the flawed U.S. intelligence on weapons of mass destruction in Iraq — displayed with much fanfare at the U.N. by former Secretary of State Colin Powell. "Unquestionably the failure to find weapons of mass destruction in Iraq has led some people to question our goodwill and credibility," Bolton responded.

He noted that the United Nations has both strengths and weaknesses and said that if confirmed he would try to help forge a stronger relationship between the United States and the United Nations, "which depends critically on American leadership." He said he aimed not just to promote American interests at the world body.

Bolton also took a critical tack, saying the U.N. General Assembly needs to focus more on human-rights violators and international terrorism.

"We must work to galvanize the General Assembly to focus its attention on issues of true importance," he said.

"Sadly, there have been times when the General Assembly has gone off track," he added, citing the "abominable" resolution that equated Zionism with racism. It was repealed in 1991, with Bolton playing a leading role as a State Department official.

'No Bully Please'

Sen. Richard Lugar (search), the Foreign Relations Committee chairman, talked at length about the controversy over Bolton, saying opponents have criticized him as "abrasive, confrontational and insensitive."

"In the diplomatic world, neither bluntness nor rhetorical sensitivity is a virtue in itself," the Indiana Republican said. "There are times when blunt talk serves a policy purpose; other times it does not."

Sen. John Kerry (search), D-Mass., said he had serious questions about Bolton's "commitment to the U.N."

"It is critical we have someone with respect for diplomacy, who believes in the United Nations despite its flaws," he said.

Added Sen. Barbara Boxer (search), D-Calif., who aired excerpts from a 1994 Bolton speech to demonstrate what she said is his disdain for the U.N.: "You can dance around it, you can run away from it, you can put perfume on it, but the bottom line is the bottom line."

Three protesters briefly interrupted the proceedings, standing up in succession with pink T-shirts and banners, one reading: "Diplomat for hire. No bully please."

Critics of Bolton cite his comment from that 1994 speech that it would not matter if the top 10 stories of the 39-floor U.N. headquarters building in New York were lost.

"There's not a bureaucracy in the world that couldn't be made leaner," responded Bolton.

Committee Democrats also have circulated a portion of a 2-year-old Senate Intelligence Committee report questioning whether Bolton pressured a State Department intelligence analyst who tried to tone down language in a Bolton speech about Cuba's biological weapons capabilities.

According to committee aides, among critics being contacted by committee Democrats is Christian P. Westermann, a department intelligence officer who has clashed with Bolton.

Committee Democrats questioned whether Bolton tried to have Westermann's job portfolio changed as a result. Bolton said he had "lost trust in him and thought he should work on other accounts."

"There is nothing there, there, and I would put it all out on the public record — all of it," Bolton said.

Secretary of State Condoleezza Rice (search) also has defended Bolton, saying he is a good negotiator and would be great in the U.N. environment despite his possible lack of subtlety.

Hanging on Chafee?

Democrats have requested an unusual second-day hearing on Tuesday for testimony from a witness who they believe will verify those reports.

One Democratic committee aide told FOX News that the case against Bolton would be "highly specific" and would emphasize "not that he's unilateral, not that he doesn't like the U.N."

"What counts now is that he may have intimidated intelligence officials," the aide said, making him unreliable when it comes to helping secure the United States.

With a 10-8 Republican majority on the panel, Bolton's nomination will likely make it to a Senate floor vote unless "something truly damaging" is revealed at the hearings, said committee member Sen. Chuck Hagel (search), R-Neb.

Both supporters and critics of Bolton have launched intense e-mail and television campaigns for and against his ambassadorship.

The true target of these campaigns is the Republican swing vote on the committee — Sen. Lincoln Chafee (search) of Rhode Island.

Democrats say they need only one Republican committee member to oppose Bolton, which would result in a 9-9 deadlock and the derailing of his nomination. All other Republicans on the committee have indicated they will support Bolton.

Chafee's staff said he was "inclined" to vote for Bolton, but also that the liberal Republican was reserving final judgment. Late last week, Chafee said the caveat was that he would switch his vote if damning new evidence were to emerge.

"You said all the rights things in your opening statement," Chafee told Bolton during the committee session Monday.

Lugar hopes to hold the confirmation vote on Thursday. If Bolton clears the panel, Senate Majority Leader Bill Frist, R-Tenn., will decide when the nomination gets a floor vote.

Asked whether he would consider joining a filibuster of Bolton to prevent a floor vote, Senate Democratic Leader Harry Reid (search) of Nevada said he wanted to see how the committee hearing played out.

"He doesn't appear to be the best guy for the job, but let the committee work on this," Reid said Sunday.

Democratic strategist Bob Beckel thought that, in the end, Democrats would not try to mount a filibuster or use other procedural maneuvers to block Bolton.

"They've stirred up a few things, but they're not going to break a pick on it. He's going to get approved, and he's going to be at the U.N., and at that point we'll see," Beckel told FOX News.

If confirmed, Bolton will succeed former Sen. John Danforth (search), R-Mo., who resigned last year after six months in New York.

FOX News' Sharon Kehnemui Liss and Molly Hooper and The Associated Press contributed to this report.