Bolton's departure had been widely expected after the Democrats took control of the senate in the November elections. But when the news broke on Monday that Bolton was leaving the post in January 4th, diplomats struggled to describe their reactions. Most described him as hard-charging and aggressive in promoting U.S. policies ranging from U.N. reform to curbing nuclear proliferation.
The 57 years old lawyer and arms control expert's achievements include persuading the Security Council to impose sanctions on North Korea after its nuclear test. He was also known for pushing relentlessly for the deployment of U.N. peacekeepers in Sudan's Darfur region, and for having Burma brought before the Council as a threat to peace and security.
But many diplomats criticized his diplomatic style as "abrasive."
Bolton clashed openly with Secretary General Kofi Annan during his 16 months at the U.N. Mr. Annan, who is due to step down at roughly the same time as Bolton, reacted to the news with lukewarm praise.
"I think Ambassador Bolton did the job he was expected to do. He came at a time when we had lots of tough issues, from reform to issues on Iran and North Korea. As a representative of the U.S. government, he pressed ahead with the instructions that he had and tried to work as effectively as he could with the other ambassadors."
China's U.N. ambassador, Wang Guangya, has often been on the opposite side from Bolton during Security Council debates. The Chinese envoy, with characteristic diplomatic understatement, questioned Bolton's style, but credited his hard work in pursuing U.S. interests.
"He's serious about the American objectives here in reforming the United Nations and he pushed hard, but of course sometimes in order to achieve the objective you have to work together with others."
A Russian foreign ministry statement Monday said Moscow hopes the next American ambassador at the U.N. will avoid what it called Bolton's "excessively tough approach." But the ministry described Bolton as "a strong professional."
Japan's U.N. ambassador, Kenzo Oshima, expressed disappointment at news of Bolton's impending departure. He credited the U.S. envoy with "exceptional skill" at a time when the U.N. faces challenging issues such as nuclear developments in North Korea and Iran.
"John Bolton was spearheading on a number of important issues. And as far as Japan was personally concerned, the North Korean missile launch in July and nuclear test in October, he really spearheaded this effort to get a Security Council resolution adopted, in a very speedy and efficient manner. I always had great admiration for his diplomatic skills."
U.N. bureaucrats made no secret of their satisfaction at seeing Bolton leave. The American ambassador's push for reform has upended many longstanding traditions and practices in the 61 years old organization.
Among the critics was Deputy Secretary-General Mark Malloch Brown, who suggested in a speech earlier this year that the United States was allowing what he called "too much unchecked U.N. bashing." When asked his reaction Monday, Malloch Brown replied "You can say I had no comment, with a big smile." Even his staunchest critics, however, agreed that Bolton has been an articulate spokesman in an often-hostile arena.