Bolton appointed US envoy to UN
Mr Bolton will be in his job for the opening of the General Assembly
US President George W Bush has formally appointed John Bolton as US ambassador to the United Nations, without waiting for approval from the Senate.
Mr Bush called Mr Bolton a "talented and successful diplomat", who would help strengthen the organisation.
He said Democrats had forced him to bypass Congress, using "shameful delaying tactics" to prevent a vote.
Mr Bolton, who has at times been a stern critic of the UN, will serve at the UN until January 2007.
Mr Bolton's candidacy did have the support of many senators but the nomination stalled because he would have needed a two-thirds majority to force a decisive vote in the Senate.
Confirmation hearings hit the headlines during the spring but became mired in debate as the Senate prepares to consider the nomination of John Roberts to the US Supreme Court.
Reforming mission
Under the terms of a so-called "recess appointment", Mr Bolton will hold office until the next session of Congress begins in 2007.
In an announcement at the White House, President Bush cited Mr Bolton's experience in foreign affairs and blamed political opponents for the irregular nature of the appointment.
"The US Senate held thorough confirmation hearings, and a majority of US senators believe he is the right man for the job," Mr Bush said.
"This post is too important to leave vacant any longer."
Accepting the role, Mr Bolton said he was "profoundly honoured" by his appointment.
He said he aimed to help reform the UN into a "stronger, more effective organisation, true to the ideals of its founders".
Democrat discontent
Before the announcement, one senior Democrat senator, Christopher Dodd, who serves on the Senate Foreign Relations Committee, described Mr Bolton as "damaged goods".
Sending an ambassador to the UN without full Congressional approval gives out the wrong signals, Mr Dodd added.
The Bush administration was keen to have a representative in place at the UN in time for the opening of this year's session of the General Assembly in September.
The US has backed reform of the United Nations Security Council, although it insists that plans to add 10 new members, including six permanent members, are flawed.
Mr Bolton served as under-secretary of state during Mr Bush's first term with key responsibility for arms control and proliferation issues.