Doesn’t play well with others. That’s the charge against John Bolton, the American ambassador to the United Nations. Other U.N. diplomats don’t like him. They complain about him the way preschool teachers complain about an irritating child — too loud, too pushy.

Tomorrow, the Senate Foreign Relations Committee will vote on whether to recommend that the full Senate confirm Mr. Bolton, who now serves in a recess appointment. A former opponent, Senator George Voinovich of Ohio, has recently voiced support for Mr. Bolton. Still, now is the moment, Mr. Bolton’s critics at the U.N. argue, to replace Rough John with a smoother envoy. Mark Brown, the U.N.deputy secretary general, has been especially vociferous in his criticism of the Bolton-led American mission.

This line of argument is weak, and for two reasons.The first is that Mr. Bolton has actually played well since he came to the U.N. last summer, brokering important agreements that strengthened both the American position and that of its allies. The second is that a docile, traditional U.N. ambassador would be bad for both America and the U.N.

But start with Mr. Bolton’s negotiating achievements. The troubles between Israel and Hezbollah notwithstanding, the biggest threats to world peace are North Korea and Iran. Just last week Mr. Bolton successfully lobbied both China and Russia to back Security Council Resolution 1695, condemning North Korea’s recent launch of ballistic missiles.

This week, he is spending a good share of his time brokering a similar resolution in regard to Iran. The resolution on Iran says Tehran must suspend enrichment of uranium for a sustained period, rather than play its habitual game of “now I am doing it, now I am not.”

Mr. Bolton is also capable of making soft concessions — endorsing the U.N.’s Millennium Goals to cut poverty and hunger, for example, as he did with President Bush last September.

But there are also older Bolton feats for the Senate to consider. Back in 1975 the General Assembly passed a resolution equating Zionism with racism. Resolution 3379, its formal name, stood on the books right through the first Gulf War. But in September 1991, shortly before the beginning of his last year in office, President George H.W. Bush tapped Mr. Bolton, then at the State Department, to start a petition for a repeal.

Bolton went door-by-door around Turtle Bay, collecting signatures, and by December of that year, the repeal was international law. Those who say that Mr. Bolton’s personality often gets in the way should note that he did this job almost without notice.

The big flaw in the anti-Bolton argument is the premise that a softer ambassador is better. This idea comes out of the Cold War. The crude reality of that period was that all that mattered on the foreign front was the arms competition between America and the Soviet Union.

The U.N. was little more than a convenient platform upon which other nations rehearsed the fiction that that they, too, had a role in geopolitics. The job of ambassadors and U.N. staff was to smooth the edges of a reality formulated elsewhere. The diplomats who served at the U.N. therefore tended to compensate for their lack of authority in sometimes juvenile fashion, placing an enormous premium on diplomatic process — getting along. The whole culture was simultaneously trivial and tragic, for it provided diplomatic cover for abusive regimes.

Since 1990, American administrations have taken the U.N. more seriously. Most Americans involved, Mr. Bolton included, harbor a desire not to repeat the hypocrisy of the Cold War. Both Clinton and Bush administrations have sought to work out differences with Iraq and other nations through the U.N.’s tools — resolutions and Security Council discussions. In this sense the institution is at least trying to function as its framers envisioned.

But a functioning U.N. has to be a place where diplomats say what they want, however unpleasant. As Mr. Bolton wrote me in an e-mail yesterday morning,”I wonder if someone is popular, how forceful is he/she at advancing their interests? We can’t always be the most popular, and that is not our goal.”

Thus, for example, Mr. Bolton led America in deciding not to take a seat on the U.N. Human Rights Council this year. Cuba, China, Pakistan, Russia, and Saudi Arabia were all elected to the council. Most Bolton critics argue that America did not want to seek a seat out of fear it would be rejected because of war prisoners at Guantanamo Bay.

But there was another motive in the American decision to refrain. To sit with Cuba, or even China, on a human rights body would be to show that America was, again, not serious about human rights. As Mr. Bolton also e-mailed me, “a strong U.N. requires a strong U.S.”

This cultural shift has infuriated those who come out of the old U.N. — hence a decision by Mr. Brown, surprising from a U.N. official, to criticize America directly in a recent speech.

At this writing it looks as if the Foreign Relations Committee will vote in Mr. Bolton’s favor, giving the full Senate a chance to consider his work. Confirming Mr. Bolton would be an act of wisdom, if only because he understands that the U.N. is no kindergarten.

The critics may not see it, but there is irony here. Veteran U.N. officials want nothing more than to see the organization become more important in the world. Yet, they are bent on ousting an American envoy who agrees with them.

Miss Shlaes is a columnist for Bloomberg News.