After five months of deadlock on Capitol Hill, Mr Bush named Mr Bolton as a "recess appointment", a procedure open to him when Congress is not in session. "This post is too important to leave vacant any longer, especially during a war and a vital debate about UN reform," the President said in a brief, low-key appearance at the White House, flanked by his new envoy and the Secretary of State, Condoleezza Rice.
Though the decision was expected, Democrats were furious, saying Mr Bolton's credibility had been fatally sapped even before he took up his post. Mr Bush had done "a real disservice to our nation," said Christopher Dodd, the Connecticut Democrat who had led what amounted to a filibuster of the nominee on the Senate floor.
As a recess appointee, lacking confirmation by the full Senate, Mr Bolton will serve only till the end of the present Congress, barely 17 months away. Another senior Democrat, Senator Edward Kennedy of Massachusetts, accused Mr Bush of "a devious manoeuvre" that "evades the constitutional requirement of Senate consent".
Though unclear as yet, the political repercussions could be considerable. In their anger, some Democrats could be tempted to obstruct confirmation of Judge John Roberts to the Supreme Court, which Mr Bush insists must be done before the high court begins its new term on 3 October.
This could lead Republicans to invoke the so-called "nuclear option", of a change in Senate rules to bypass the filibuster and allow judicial nominations to pass by simple majority. Democrats, in a minority of 45 to 55, have threatened to retaliate by using the rules to bring Congressional business to a virtual halt.
Few diplomats have attracted controversy like 56-year-old Mr Bolton. The self-made son of a Baltimore fireman, he is an outspoken neo-conservative hawk in a profession where tact and understatement are usually the watchwords.
Openly derisive of the UN, he has said the loss of 10 storeys of its headquarters building in New York would make no difference to its operations. As undersecretary at the State Department for national security issues during Mr Bush's first term, he was a constant thorn in the side of Colin Powell, Ms Rice's predecessor.
His hawkish views, akin to those of Donald Rumsfeld, the Defence Secretary, and Vice President Dick Cheney, earned him the reputation of being "the Pentagon's man at State". Through weeks of contentious confirmation hearings in the spring, Democrats resurrected various Bolton statements to argue, in the words of one senator, that despatching him to New York would be "like sending a bull into a china shop".
But other allegations bedevilled his nomination. Mr Bolton was said to have abused subordinates and twisted intelligence on Iraq and other countries to suit his neo-conservative views. He has also been accused of concealing the fact he had given testimony to a grand jury while an official at State.
At the UN itself, all was politeness yesterday. Kofi Annan, the secretary general, said he was looking forward to working with the new ambassador, and avoided taking sides on the manner of his arrival. It was Mr Bush's prerogative to appoint Mr Bolton as he wished, Mr Annan said.
Even so, this is the first time in memory that the most important diplomatic field post has been filled without Senate approval. That and his short time in post lead many to feel that his authority will be reduced.Reuse content