By a vote of 42 to 56, Democrats managed to garner enough support for a procedural maneuver to prolong debate on Bolton's nomination.
Democrats needed the votes of just 41 senators to delay a confirmation vote from going forward.
After the vote, Senate Majority Leader Bill Frist bitterly remarked that the move bore an uncanny similarity to the "filibuster" technique that Democrats employed to block Bush's judicial nominations for years, and which very nearly led to a massive partisan showdown earlier this week.
"It looks like we have yet again another filibuster," Frist said. Senate Democrats said the additional time would allow them to pressure the Bush administration to produce additional classified information on Bolton.
The sought-after information dealt with congressional testimony written by Bolton about Syria's alleged attempts to procure weapons of mass destruction, and efforts by Bolton to obtain the names of several intelligence analysts whose identities were revealed in several top-secret reports.
"We don't want this to be a diversion from the work we have to do here"
Harry Reid, Democratic Senate minority leader
Senate Minority Leader Harry Reid assured Republicans that Democrats were not trying to block a confirmation vote, but needed the information to fully vet the controversial nominee.
Not trying to block
"We don't want this to be a diversion from the work we have to do here," Reid said, adding that Democrats had no choice but to block the nominee until the White House provides the documents.
State Department spokesman Richard Boucher earlier on Thursday said the department, including his boss Secretary of State Condoleezza Rice, has bent over backwards to provide all the data needed for senators to vet Bolton.
"We've spent hundreds of man hours. We've produced extensive amounts of documents. Over 25 hours of hearings and business meetings were devoted by the committee to reviewing the nomination," Boucher told reporters.
"Once again, we reiterate the secretary and the president believe he's the right man for the job. We hope to see him at the United Nations very soon," he said.
In addition the impasse with the White House over the intelligence documents, Democrats have a litany of complaints against the nominee himself.
They accuse Bolton of bullying past staff members and manipulating intelligence to suit his political agenda, and say he is temperamentally ill-suited for the highest levels of diplomacy.
"The United Nations is the world's preeminent diplomatic body," said Senator Ted Kennedy said on the Senate floor, summing up Democrats' objections to Bolton.
"Now more than ever, America needs to put our best face forward to the international community. We can and should do better than John Bolton," Kennedy said before the vote.
Adding to their objections, Democrats said on Thursday that Bolton would be a damaged UN ambassador, after the bruising series of hearings and investigations into his past.
Senate Republican's have been
divided in their support for Bolton
"What credibility will he have?" said Democratic Senator Paul Sarbanes. "We need a credible spokesman at the United Nations."
Bolton, who is currently the US undersecretary of state for arms control and international security, has fervent Republican supporters who said he is precisely the US envoy the world body needs after scandals in the UN-administered oil-for-food program in Iraq, sexual misconduct by UN peacekeepers, and other problems.
In reprising one of the most often-invoked reasons for approving Bolton, Republican Senator John McCain said he should be confirmed primarily because he is President George Bush's pick.
"Elections have consequences. One consequence of President Bush's reelection is he has a right to appoint officials of his
"It's not my choice, or any other senator's, but the president's choice," McCain said. Bolton's confirmation vote now will be postponed until after the Senate returns from a weeklong holiday in June.