The NATO defence ministers, who are meeting Thursday and Friday, want to start learning the military and political lessons of the Iraq war, which sparked an unprecedented crisis within the 19-member organization.

One senior US official said NATO had undergone a "near-death experience" in February, when three anti-war countries blocked the Alliance from providing defensive support for Turkey ahead of the Iraq conflict.

"But we've healed an awful lot in a short time," said another diplomat, trumpeting agreements for NATO to take command of peacekeepers in Afghanistan and to support the setting up of a stabilization force in Iraq.

Rumsfeld called Wednesday on US allies in Europe to unite, despite bruising differences over Iraq, to confront the looming dangers of weapons of mass destruction, rogue states and terrorism.

"It is really a matter of attitude, of the vision the countries bring to the transatlantic relationship and to the challenge we all face in the years ahead," he said in a speech in Germany, from where he flew into Brussels.

Iraq is top of the agenda at the start of the two-day meeting on Thursday, when Rumsfeld and his British counterpart Geoff Hoon will brief their fellow ministers on the situation on the ground.

"There is still a lot of work to be done on learning the lessons of the Iraq war," said the senior US official, speaking on condition of anonymity.

The defense ministers are likely to focus in their formal talks on the military lessons learnt, although the wider political questions will no doubt be discussed, said one diplomat.

NATO agreed earlier this month to support Poland in establishing a multi-national "stabilization" force in Iraq, of which Warsaw -- a key European ally of Washington during the war -- is to command one sector.

The United States has made no secret of its wish for NATO to be even more involved in Iraq. "We hope that NATO will in the future elect to play an even broader role but I don't think this will be on the agenda," said the US official.

The other key subject for discussion is NATO's military restructuring. The 19-member Alliance -- set to expand to 26 nations next year -- had already vowed to reorganize itself after the Cold War.

But September 11, 2001, accelerated that process, leading to a decision in May 2002 that NATO should conduct operations outside its traditional European theatre of activities and culminating in a landmark summit in Prague last November which was dubbed the Alliance's "transformation summit."

To that end NATO is reorganizing its military structure, replacing the two current commands -- one in Europe, one in the US -- with a single operational commander based in Europe and a "transformation commander" based in the US.

"The overall aim is to adapt the Alliance from a static force waiting for the Soviet tanks to roll in, to a mobile, flexible force ready to take out the terrorist threats wherever they appear," said one diplomat.

The Brussels meeting comes only a week after NATO foreign ministers met in Madrid, where some participants even raised the possibility of a role for NATO in a Middle East peace settlement.

Such an option is not on the defense chiefs' agenda for Thursday and Friday.

"We have enough on our hands with the Afghanistan and Iraq operations," said one diplomat.

Another item likely to fuel discussion in the corridors will be finding a successor to NATO head George Robertson, who steps down in December after four years at the helm of the world's premier military alliance.

According to one diplomat, the field has narrowed to two names -- Portugal's European Commissioner Antonio Vitorino and Norwegian Defense Minister Kristin Krohn Devold, who if successful would be the first woman in charge of NATO.

"But I do not expect a decision before September and other candidates may appear by then," he said.

WAR.WIRE