The Republican-controlled Senate Foreign Relations Committee (search) voted 10-8 in favor of sending Bolton's nomination forward to a full floor vote, but without a recommendation.
Committees that are unsure about a nominee may send a vote to the floor without an endorsement, to allow the full Senate to decide. Bolton should have an easier time there, where Republicans hold a 55-45 majority.
Senate Majority Leader Bill Frist, R-Tenn., plans to hold off on a floor vote until after the Memorial Day break so that lawmakers can resolve a battle over judicial nominees, a source told FOX News.
During deliberations on Thursday, Democrats assailed — and Republicans were forced to acknowledge — several disturbing allegations against the undersecretary of state for arms control regarding his behavior toward colleagues and subordinates.
Most remarkably, Ohio Republican George Voinovich (search), who gave no prior indication of how he would vote, laid into the nominee, calling him "the poster child of what someone in the diplomatic corps should not be."
But the senator, considered the swing vote in Bolton's nomination, stopped short of saying he would vote Bolton down, instead urging the committee to move the decision forward to the floor without recommendation and "let the Senate work its will."
Voinovich told reporters during a recess that he would vote against Bolton in a Senate floor vote. He urged all senators to carefully consider the hundreds of pages of testimony describing Bolton's allegedly unprofessional behavior during his State Department post.
"After poring over hundreds of pages of testimony ... I believe John Bolton would have been fired if he worked for a major corporation," Voinovich said at the committee hearing. "This is not the behavior of a true leader or the face of the United States to the world community."
With "all things being equal, it is my proclivity to support the president's nominee," Voinovich concluded, but "in this case, all things are not equal.
"I have come to the determination that the United States can do better than John Bolton," he told committee Chairman Richard Lugar (search), R-Ind.
The other Republicans who wavered on the nominee — Sens. Lincoln Chafee (search), R-R.I., Lisa Murkowski (search), R-Ala., and Chuck Hagel (search), R-Neb. — were less forceful in their criticisms, but joined Voinovich in withholding recommendation.
Voinovich has been vocal about his wariness of Bolton's credentials for weeks. Last month he helped Democrats on the committee win a delay on a vote by requesting more information following fresh allegations of misconduct.
His reservations about Bolton seemed to take the administration by surprise, FOX News political contributor William Kristol said, adding that President Bush spoke to the senator personally Wednesday night.
Ranking Democratic committee member Sen. Joe Biden (search) of Delaware seemed taken aback at Voinovich's remarks, saying what he had prepared to say would be "redundant and not as eloquent."
The panel's eight Democratic members, who unanimously opposed Bolton's appointment, failed to get the support of at least one Republican to keep him from getting an up-and-down vote.
Bolton, one of the most contentious nominees of Bush's presidency, has had to fend off accusations from both sides of the aisle that he is an intemperate bully who has no tolerance for differing points of view.
More seriously, he is charged with dismissing subordinates whose interpretations of intelligence did not match his own — invoking probably the biggest embarrassment of Bush's tenure, a war declared on Iraq based on faulty and forged information.
"We've suffered the tragic consequences of intelligence failures, and one of the casualties has been the credibility needed to bring allies to our side. Why would we ever choose as our next U.N. Ambassador a man who even senior Bush administration officials believe stretches intelligence to fit his ideological views?" said Democratic committee member John Kerry in a statement Thursday.
The administration has stood by Bolton, even as the gruff State Department official — known for his thick, white mustache — has become fodder for late-night television.
The White House has called a vote for Bolton "a vote for reform in the U.N.," and Republicans including Sen. John Sununu (search) agreed.
Alleged "bad behavior in diplomatic circles can be effective, can be the right thing to do at the time for the United States," the New Hampshire senator said.
"I think we need to be careful about reading too much into an individual's behavior at a particular time and a particular place, and suggesting that it renders them unqualified for any particular position," Sununu added.
While Murkowski admitted she disagreed with Bolton's management style and found remarks he has made in the past "inflammatory," she said a "hard-charging" individual was needed if Washington wanted reform in the United Nations.
"Now is not the time for the United States to send an individual to the United Nations that is just going to be a caretaker, but one who will be proactive in pushing the United States' agenda," she said.
And as with most of her fellow Republican panelists, she summed up her argument by saying the president "deserves to have the individual he believes will be the most effective in that position."
Democratic members of the committee released a summary of concerns about Bolton to their Republican colleagues on Thursday.
In the report, obtained by FOX News, the Democrats outlined what they see as four patterns of conduct that disqualify Bolton from the ambassadorship: attempts to get rid of intelligence analysts with whom he disagrees, shaping intelligence in testimony to suit his views, abusive behavior toward colleagues and subordinates, and testimony before the committee that turned out to be inaccurate.
Written testimony by a former U.S. Agency for International Development contractor that an enraged Bolton chased her through a Moscow hotel lobby and repeatedly banged on her door more than 10 years ago has caused pundits and lawmakers alike to wonder if America's top diplomat in the U.N. shouldn't be more diplomatic.
Bolton's two biggest tasks, should he be confirmed as ambassador to the U.N., will be persuading North Korea and Iran to drop their nuclear ambitions.
It is unclear how effective Bolton will be in that regard, especially since he is already considered an enemy by North Korea. The country barred him from six-way talks on its nuclear program two years ago after he called Kim Jong-il a "tyrannical dictator."
A furious Pyongyang lashed out at the State official, calling him "human scum" and a "bloodsucker," an indication he was unlikely to sway them to drop their nuclear ambitions.
Murkowski on Thursday said she had found Bolton's actions to be "inflammatory at a time when we were trying to promote diplomacy in the region."
Sen. Paul Sarbanes, D-Md., argued Bolton already had several years to prove himself an effective diplomat on the Korean peninsula.
"The approach advocated by Mr. Bolton on North Korea simply has not worked," Sarbanes said, adding that the diplomatic standoff was "terminal" now that the country is believed to have built six to eight nuclear weapons since the crisis began.
But Republican supporters have praised Bolton's bluntness, saying a hard line is needed to deal with rogue regimes.
"Let the Democrats explain why you don't want a tough guy like John Bolton going up against Iran and North Korea," Kristol said.
Critics counter that such harshness is inappropriate for a diplomatic post.
Quoting former U.N. Ambassador Jeanne Kirkpatrick, the Democratic panel members said it is the representative's job "'to operate in a low-key, quiet, persuasive and consensus-building way' to advance U.S. interests."
The committee members concluded: "Mr. Bolton has proved himself incapable of operating in this manner."
Bolton, 56, has held his current post at the State Department since May 11, 2001. A lawyer, he has previously worked at several prominent Washington law firms as well as the Justice Department in the 1980s.