The U.N.'s Day Of Reckoning.(bombing of United Nations headquarters in Iraq)

Holbrooke was U.S. ambassador to the United Nations from 1999 to 2001.

The bombing of the U.N. headquarters in Iraq was the United Nations' 9/11. Now a stricken organization must regain its equilibrium, knowing that its personnel are a target in Iraq, and perhaps elsewhere.

As always, though, the future of the United Nations lies not in what is said or done in the dispirited buildings along New York's East River, but in what the United Nations' leading members do to strengthen the organization they created in 1945 to deal with just such a challenge. And the primary role should be played by the organization's founding member, its largest contributor, its host country. After all, the attack on the U.N. headquarters was also an attack on the United States, since the United Nations' work in Iraq was clearly in support of American policy objectives.

Yet at this crucial moment the leadership needed from Washington is curiously missing--despite the fact that the United States needs a strong United Nations. If the United Nations is forced to pull out its personnel--men and women working for the key U.S. goals of security, political stability, and economic and social development--American policy in Iraq will also be at risk.

Sergio Vieira de Mello, the brilliant and charismatic U.N. leader who died in the bombing, personified the potential of the United Nations' relationship with the United States. In his extraordinary career, Sergio--my friend for more than 20 years--worked in an astonishing collection of dangerous spots, including Bangladesh, Cambodia, Lebanon, Bosnia, Rwanda, Congo, Mozambique and East Timor, where his experience in guiding a war-torn half-island to independence had direct relevance to the challenges in Iraq. While loyally serving his organization, Sergio was usually advancing America's long-term interests as well. He saw nothing incompatible in this. On the contrary, he believed passionately that the goals of the United Nations and those of the United States were symmetrical, if not always identical. He was a great humanitarian, but he was also a wise political operative whose final days were spent trying to guide a confused American mission on how to deal with the chaotic political scene.

The days immediately following the death of Sergio and his colleagues were sorry ones for the United Nations. Instead of the tragedy's triggering a coming together of major nations to lay out a plan to protect U.N. personnel, it produced an embarrassing ...