Apparently setting aside the former posture of unilateralism that placed his administration sharply at odds with ancient allies on issues like missile defense and the environment, and alienated many other UN members, President George W. Bush now says he looks toward the UN for help to rebuild Afghanistan.

This can come, he believes, after American and British air strikes -- and possible ground action -- have reduced the country to rubble and driven out or killed its grim Taliban fundamentalist rulers. Their ouster is Washington's aim in response to what the US and the UK believe is the Taliban's clearly established complicity in the destruction of the World Trade Center and part of the Pentagon in the worst terrorist outrage in history, on Sept. 11.

British Prime Minister Tony Blair, now serving in effect as Bush's point man, has declared the evidence conclusive that Osama bin Laden, a reclusive Saudi billionaire alleged to be receiving sanctuary and support in Afghanistan -- although some experts say he may already have moved to safer quarters -- was the mastermind behind the attacks, which took more than 5,000 lives, caused billions of dollars' property losses and reduced the world economy to shambles.

James D. Wolfensohn, president of the World Bank, has said that poor developing countries will suffer disproportionately in a global recession now considered virtually inevitable.

As John Ashcroft, the US attorney general, cautioned people in the US to expect new terrorist attacks, Vice President Dick Cheney said bluntly he suspected that scattered outbreaks of anthrax -- hitherto rarely recorded in the US -- had a terrorist connection. There were reports that a mysterious white powder, possibly containing anthrax baccili, had been mailed from an address in Florida. The UN is said to have been on the mailing list, which included NBC.

Director General Gro Harlem Brundtland and epidemiologists at the World Health Organization are watching the situation closely, in cooperation with the US Center for Disease Control. Meanwhile, New York Mayor Rudolph W. Giuliani sought to downplay fears of spreading anthrax infections -- the disease is said not to be contagious -- after an NBC staffer at Rockefeller Center was diagnosed a sufferer. He said she was recovering following a course of antibiotics.

The possibility that terrorist plotters might acquire a nuclear device or employ chemical weapons in further outrages raised new alarms. As sanitation department trucks and Nassau County Police cruisers -- brought to Manhattan to help out the city's severely stretched law enforcement system -- closed the UN perimeter to all general traffic, senior officials worked to calm nervous staff. The UN is conscious that the headquarters, along with the Empire State Building and the Holland Tunnel, were on the terrorists' list of targets when the World Trade Center was car-bombed in 1993.

The diplomatically-immune UN buildings lack a sprinkler system -- mandatory in other office towers -- and could be especially vulnerable to fire. Security officers and city police and firefighters have conducted precautionary evacuation drills.

As the US and Britain continued to pummel suspected terrorist enclaves and other targets mapped by allied intelligence, President Bush disclosed that he foresees a central role for the UN in nation-building in Afghanistan after the Taliban have been toppled. However, he studiously avoided that term, preferring instead the phrase "stabilization of a future government." UN officials welcomed the challenge.

Annan shared the alarm felt by many in the UN after US Ambassador John D. Negroponte delivered Washington's warning that the war against international terrorism might have to go beyond Afghanistan to "further actions with respect to other organizations and other states." Iraq came quickly to mind. Could the Bush administration now resist the temptation to take out Saddam Hussein, once and for all?

Aides said the Secretary General believes that extending the conflict to Iraq -- said to be advocated by administration hawks but to be opposed by Secretary of State Colin Powell -- would be "a disaster" and should be resisted at all costs. Annan talks often to Powell and will certainly have relayed his strong objections to adding Iraq to the allies' targets.

In the event, it transpires that the US may have more distant places in mind, specifically Al Qaeda operatives' suspected terrorist cells in Indonesia, Malaysia and the Phillipines. Manila is said to be a dangerous hub.

Prime Minister Blair is Annan's backer in opposing a military attack on Iraq, beyond the frequent aerial sorties that the US and the UK have long conducted. Blair issued assurances that the two allies would not expand the Afghanistan conflict without first consulting other members of the anti-terrorist coalition. The Security Council in response to Sept. 11 has already expressly recognized the right of self-defense and use of force, if necessary.

For his part, Annan would have liked to see a UN umbrella placed over anti-terrorist military operations but appears to be satisfied, for the time being, with Council decisions that have provided what is in effect its seal of approval for Washington's and London's robust military measures.

The Secretary General also is among those who have little or no doubt about bin Laden's role in last month's tragic events. He interprets the renegade Saudi's videotaped statement broadcast by the satellite TV station al-Jazeera as an implicit acknowledgement of responsibility for the murderous attacks. The six foot five inch, 160lb. terrorist leader, who is reputed to pray five times a day, declared his belief that Allah approved the death and destruction at the Twin Towers and the Pentagon, the world's biggest office building.

This tragedy was not mentioned specifically in the citation by the Norwegian Nobel Committee which named the UN and Annan to share this year's Peace Prize, the 100th since the award was initiated in the will of Alfred Nobel, a citizen of Sweden and the inventor of dynamite. The committee had searched all summer for honorees appropriate for this centennial Prize and finally chose from among 136 contenders, including Pope John Paul II and the International Committee of the Red Cross. The decision was made on Sept. 28, just 17 days after the terrorist attacks. Although the committee kept its counsel until Oct. 12 when the announcement was made, Annan was known to be a nominee and newspapers in Europe quickly declared him the favorite. They were not wrong.

The Secretary General, who will collect the Prize (worth $943,000, which he and the UN will share) in Stockholm on Dec. 10, Nobel's birthday -- which happens also to be Human Rights Day -- called it "a great encouragement for me personally and for the Organization and the way the world has reaffirmed the indispensable role this Organization should play in international affairs."

He said also that it was a "shot in the arm that is really deserved and needed." Rising to the occasion, Richard Ryan, Ireland's UN delegate who heads the Security Council this month, summoned a special meeting to record that body's pleasure at the honor, which Annan promptly proclaimed was shared also by the Council, the primary international organ for the maintenance of peace and security.

For years during the cold war, the Council was hamstrung by East-West divisions and often paralyzed by Soviet or Western vetoes. The Nobel committee noted how this has changed, stating in its citation that today it is possible "for the United Nations to perform more fully the part it was originally intended to play."

Lavish in praise of the 63-year-old Secretary General, an American-educated native of Ghana who has spent most of his adult life in UN service, the committee said he had been "preeminent in bringing new life to the Organization" while emphasizing its obligations in the area of human rights and rising to "such new challenges as HIV/AIDS and international terrorism."

Annan has led the global campaign against AIDS, which has claimed millions of lives, continues to add new sufferers and rages with especially fierce intensity in his own continent of Africa. He instituted a $10 billion fund to combat the pandemic, which will begin work later this year with help from major donors, including a first contribution of $200 million from the US.

The Secretary General is lauded in the Nobel citation also for using the UN's "modest resources" with greater efficiency. In part, this is how he rose to lead the Organization which had sunk into disarray under Boutros Boutros-Ghali, who was dismissed in efect when the US vetoed his candidature for a second five-year term. Annan's term would expire at the end of this year but has already been extended another five years by unanimous decisions in the Security Council and the General Assembly. Thus, he will be in charge of the Organization during the anti-terrorism war and its aftermath.

He is the second UN chief to have been honored with the Nobel Peace Prize. The first, posthumously, was Dag Hammarskjold of Sweden, who was killed in an air accident 40 years ago on a peace mission to the Congo. Ralph J. Bunche, an African-American former State Department official who became a UN under secretary, also received the Prize, for his work as the Middle East peace mediator.

As the UN prepares for possible new responsibilities both in Afghanistan and in the fight against terrorism, a new attempt is under way to agree on a definition of terrorism -- necessary if the Organization is ever to conclude an international convention against it. Members have struggled since 1972, when the issue was first placed on the agenda, but were stymied by such differences of opinion as whether, in certain cases, what some may call a terrorist is, for others, a "freedom fighter." That was an argument with special resonance during the campaign by black South Africans against their country's apartheid regime. (Nelson Mandela was jailed 27 years for "terrorist" activities.)

On the military side, Annan and his aides are urging the US and the UK to be mindful of their responsibilities as permanent members of the Security Council. This does not confer the status of global enforcers, but both Washington and London were quick to notify the Council of the military measures begun on Oct. 8, which already had the UN's implicit blessing because of the self-defense clause in Article 51 of the Charter.

The US and the UK are expected to keep the UN informed, but tying military action more closely to the Council's say-so could create problems for them. President Vladimir Putin has been surprisingly cooperative so far and the Chinese have made known their worries about internal Islamic extremism, but great power unity in the Security Council is seldom automatic.

A rising toll of Afghan collateral casualties, inevitable in conflicts like this, may stir more angry street protests, not only in countries where there already is a perception that not only terrorism but Islam itself is a target but also by the West's sizable contingents of what used to be called peaceniks. These are the descendants of protesters who hated the Nazis and Japanese imperialism yet would rather not have had their countries take up arms against those evils. Some of them, more noisy than numerous, have been heard around Manhattan's Times Square in the current crisis. Their numbers may mount. Those who made anti-globalization their cause may have found an even more compelling target.

Worried about the Muslim masses -- Islam claims one billion adherents, one-sixth of world population -- Annan sent a message to foreign ministers from states members of the umbrella Organization of the Islamic Conference to be sure to stress and make more widely heard and accepted that the Muslim religion is "inherently peaceful and tolerant." Bush, who visited a Washington mosque, and Blair both have made the same point in a bid to reduce suspicions about and hostility toward Muslims.

"For the United Nations, it is essential that the global response to terrorism be truly universal and not divisive," Annan said in his message, delivered by Ibrahim Gambari, a former UN ambassador of Nigeria. Also, said the Secretary General, the people of Afghanistan are not to blame for the Taliban's actions and now are in desperate need of aid. "It is also vital that the international community now work harder than ever to encourage a political settlement to the conflict in Afghanistan," that has been going on for more than two decades, Annan said.

There is more than enough economic fodder from Sept. 11 to keep the anti-globalization crowd busy as they trim their sights and aim at new objectives. A UN report issued just four weeks after the New York and Washington attacks concludes that these will have far-reaching effects and slow further a global economy that was already growing at its lowest rate in a decade.

"The shock is expected to reverberate through the world economy and global financial markets in the coming months," UN experts say. Military and political reactions to the terrorist assaults will "greatly amplify" existing uncertainties about the short-term outlook and are likely also to have significant long-term implications.

The report does not use the R-word, recession -- a state which some analysts say the US has already entered -- but it does anticipate a worse than previously expected downturn for America, with "an absolute decline in gross domestic product in the third and fourth quarters." (The fourth quarter now is here, of course.) The most severely affected developing countries economies are expected to be those of South and East Asia, where GDP projections for this year have dropped from 4.1 percent to 1.7 percent.

Canada is expected to feel the greatest impact from its southern neighbor's decline, but Japan's performance will be the weakest of all the developed countries, says the UN report.