The 26-member NATO alliance holds a summit Monday and Tuesday in Istanbul. The meeting is being held as NATO is being asked to play a role in Iraq, even as its mission in Afghanistan is suffering. The alliance is still trying to define its place in a post-Cold War world and is having problems adapting to new global security challenges.

Diplomats and analysts say most NATO allies have lacked both the agility and the willingness to face up to 21st Century threats that emanate from outside the alliance's traditional operating area in Europe.

Fifteen months after the Iraq War began, the divisions that it caused have still not healed. But most observers say they will be downplayed at the Istanbul summit.

Still, reverberations from the aftermath of the conflict will be on the table, especially since Iraq's interim prime minister, Iyad Allawi, has asked the alliance for help in training Iraqi security forces and other unspecified technical assistance.

President Bush has acknowledged that NATO countries, 16 of which are involved in Iraq, are not likely to contribute more troops there, but he has expressed hopes that some of the allies will help train Iraqi forces.

Italy has offered to do so. Even Germany, which, along with France strenuously opposed the Iraq War, says it, too, could help in the effort as long as the training is done outside Iraq.

NATO Secretary-General Jaap de Hoop Scheffer says it is up to allied leaders to decide how they should help Iraq, but he told reporters this week that he does not think they should turn down the Iraqi request.

"There is a fully legitimized interim government in Iraq with a prime minister who writes a letter to NATO," he said. "NATO should never slam the door in this prime minister's or this government's face."

France, which opposes any NATO presence in Iraq, has not closed the door on NATO troops training Iraqis, but it wants further discussions on the issue. So, as Mr. De Hoop Scheffer's deputy, Alessandro Minuto Rizzo, puts it, there is no guarantee that a decision will be reached in Istanbul.

"NATO works by consensus, consensus by the governments, so there could not be any intervention anywhere unless 26 governments decide so," he said.

The debate on how NATO can help Iraq comes as many of the allies with forces there are growing uneasy with the deteriorating security situation. Spain has already pulled its troops out after a change of government. The Poles want a multinational NATO force to take over their operational area. Other countries have set time limits for their forces' presence in Iraq. Still, British Defense Secretary Geoff Hoon says the allies can find a role to play.

"I believe there is a role for other countries to become engaged even if they choose not to put their forces on the ground to face the kind of threats that are currently facing the coalition forces," he added.

While the NATO leaders attempt to find common cause on what their alliance can do in Iraq, they will also have to face up to an embarrassing problem NATO has encountered in Afghanistan, where it commands an international peacekeeping force. NATO nations have been slow in providing troops and equipment to allow the force to expand its operations beyond Kabul, the Afghan capital.

NATO has promised to create at least five provincial reconstruction teams, made up of both civilians and troops, to help guarantee security for nationwide elections in September. The alliance says it will make good on its pledge, but Mr. De Hoop Scheffer has had to virtually beg the individual allies for contributions and what he has been given is still far short of NATO's goals.

Analyst Julian Lindley-French, of the Geneva Center for Security Policy, says NATO's credibility is at stake in Afghanistan and that the alliance cannot afford to fail there.

"At the end of the day, like it or not, Afghanistan is going to be a litmus test for much of the world that could be hostile to us over our intent and our capability in this field," Mr. French said.

The Secretary-General says he will press NATO leaders to consider ways of matching political commitments and military resources, such as common funding for crucial capabilities like transport aircraft and helicopters so that the alliance can avoid a replay of its experience in Afghanistan.

A major cause of these shortfalls is that most European allies have stagnant or declining defense budgets and, in many cases, have not reconfigured their forces from a static Cold War posture to meet the requirements of crisis operations far from home. Only four percent of the 1.2 million men and women in uniform in European NATO nations are deployable. And calling for an increase in defense spending is the kiss of death for a European politician these days. Only Britain and France, apart from the United States, are judged to have the kind of highly mobile forces NATO needs.

But if NATO cannot reform and become more agile, Mr. Lindley-French says the United States may never be convinced that the alliance offers an efficient alternative to the kind of coalition of the willing that it put together in Iraq.

"If the major powers, particularly the United States, does not get agreement inside NATO, it will always decide to act outside," he added.

U.S. officials like John Koenig, the number two man at Washington's mission to NATO, say that the United States is committed to working with NATO, when it can.

"For the United States, with its global responsibilities, NATO has not always been the only choice for operations, but it is certainly our preferred choice," he noted.

U.S. and British diplomats say that if NATO is to continue being relevant in the 21st Century, then European members have to spend more money on defense and transform their armies into flexible fighting forces that can operate alongside those of the United States. If they fail to do so, policymakers on both sides of the Atlantic may begin to ask whether NATO is really worth saving.