June 20 (Bloomberg) -- Republicans in the U.S. Senate failed again to gain a vote on President George W. Bush's nomination of John Bolton to be ambassador to the United Nations.

The Senate voted 54-38 on a motion to end debate on Bolton. Republicans needed 60 votes to override the Democrats' filibuster. Republicans hold a 55-44-1 majority in the 100-member chamber.

Senate Republican Leader Bill Frist accused Democrats of ``obstructing a highly qualified nominee'' and ``doing harm to our country.'' Bolton, Frist said, ``deserves a vote and the American people deserve a strong, principled voice in the United Nations.''

Democrats, led by Joe Biden of Delaware and Chris Dodd of Connecticut, say Bolton lacks the diplomatic skills needed to be UN envoy, that he abused subordinates and once tried to pressure intelligence analysts to change reports to conform to his views.

Supporters of Bolton, 56, dispute the criticism and say he will strongly defend U.S. interests and carry out needed reforms at the UN. He has won Senate confirmation to government posts on four previous occasions.

Bolton's nomination was sent to the Senate March 17 and the delay on his nomination is an embarrassment for Frist, a Tennessee Republican, as well as the White House.

Democrats say no vote should be held until the Bush administration releases classified information involving Bolton that they sought weeks ago.

To contact the reporter on this story: Jeff St.Onge in Washington at jstonge@bloomberg.net.

Last Updated: June 20, 2005 18:48 EDT