THE political problems are formidable. In a speech in Chicago last Thursday, Blair tackled the question of Nato's role in the world. Having won the cold war without firing a shot, what is its purpose? The prime minister believes that civilised countries have a moral duty to uphold their values elsewhere, by force if necessary.

The prototype of this vision is, of course, Kosovo. But Nato's campaign there has also highlighted the many different interpretations that civilised countries place upon moral duty. Just as Nato nearly fell apart over how best to help the people of Bosnia, its greatest achievement in the Kosovo crisis so far has been to keep all its members on board in the face of extreme differences of opinion, which were only too plain at the anniversary bash in Washington.

Costas Simitis, the Greek prime minister, questioned the entire rationale for the air campaign. "The air raids have not led to the end of ethnic cleansing but rather have intensified it," he said. "Milosevic has not lost his appeal with the Yugoslav people. On the contrary, he has strengthened it."

Two public opinion polls that were published in Athens last week indicated that more than 96% of the Greek people were against the bombing. Faced with not only mounting domestic unrest but also a humanitarian crisis right on his doorstep, Simitis is maintaining official support for Nato's military actions while insisting at the same time that a political solution must be found.

George Papandreou, the foreign minister, said after meeting Albright for 45 minutes in Washington that she had made no request for use of the northern Greek port of Thessaloniki - strategically the only convenient route for the passage of Nato troops and heavy armaments if a war is fought in Kosovo.

Italy, the launchpad for most of the Nato airstrikes against Yugoslavia, is almost as nervous as Greece. Opinion polls show that most Italians are against the bombing raids and that only 30% are in favour of a ground offensive.

The centre-left government, the first post-war administration to include Marxists, has repeatedly upset Washington. Italy's ambassador to Washington, Ferdinando Salleo, has been bombarded with irate telephone calls from the White House demanding explanations for the views floated in Rome. Members of the Communist and Green parties in the coalition have threatened to bring it down if it supports a ground attack.

"If the operation could be presented as a peace mission, it could pass parliament with some difficulty," said Sergio Romano, a political columnist and former diplomat. "If, instead, they have to go to Kosovo to fight a war, this government is finished."

Gerhard Schröder, the German chancellor, faces an even tougher conundrum. The Greens, the junior partner to his Social Democrats in the government, are deeply uncomfortable with the air campaign.

A decision to send in Nato ground troops would destroy the coalition, political analysts believe. But Kosovo could well bring down the government before then if, as seems likely, the Greens' party congress on May 13 votes against the air war. Dozens of local party groups have passed resolutions against it and the party executive believes that at least 50% of the party rank and file opposed the war "on principle".

Among the many parliamentarians and regional Green leaders who have signed a mass petition calling for an immediate end to the Nato "war of aggression" - a form of war specifically outlawed by the German constitution - is a Green member of the
government, Gila Altmann, a state secretary in the environment ministry.

France, despite making the second strongest contribution to the air war after America, fears that its fragile political consensus could be shattered by a ground offensive. The communist members of Lionel Jospin's ruling coalition have so far stood by quietly as France has abandoned its traditional Gaullistdisdain for American-led military ventures in favour of a whole-hearted embrace of Nato's Balkan strategy. But the prospect of a ground war evoked an angry riposte from Charles Hue, the Communist party secretary.

"The Americans are giving the impression of wanting to force their allies' hands," he said. "France's reply must be unambiguous: there can be no question of engaging ourselves, at the heart of Europe, in a spiralling inferno of which we know neither the limits nor the consequences."

Jean Marie Le Pen, leader of the extreme right National Front, also complained of "American domination". He added: "The spectacle of Europe and France clinging to Clinton's boots in this war of cowards and moralising barbarians is nauseating,
vile and intolerable."

Blair's own problems at home are minor by comparison. "Tony looks tired, but the most striking thing is that he isn't so worried about Kosovo," reported a member of the government.

One minister is rumoured to be an outright oppone of the war, with others holding at least some privat doubts. None, however, dares speak up because of the lack of substantial parliamentary or grassroots opposition. Only 11 of the 417 Labour MPs voted against the war in a Commons vote last Monday. "It hardly qualified for the description of rebellion," said one Blair loyalist.

The usual band of hard left critics is divided. While Tony Benn has taken to touring parliament showing off his second world war campaign medals as he preaches against the bombing raids, Ken Livingstone argues just as forcefully for armed intervention.

Clare Short, usually the nearest thing to a left-wing totem inside the cabinet, denounced the 11 war rebels as "a disgrace to the Labour party" and compared them to those who appeased Hitler. And Cook, the nearest thing to a left-wing anti-Blairite faction leader, is in the war cabinet as foreign secretary, vigorously helping to conduct the war.

"I have never been a pacifist," Cook told The Sunday Times when challenged over his unilateralist past. "I have always believed it is right to fight evil."

NOW Nato is saying officially that troops will go to Kosovo only after "Belgrade has unequivocally accepted" the alliance's demands. But it has left open the possibility that this policy could change. Officials say allied governments would build up their forces in the region so as to be ready to enter Kosovo with or without Milosevic's approval.

Clinton, for his part, has outlined three scenarios that would constitute victory for Nato. Under the first, Milosevic would "cut his losses" and give in to Nato's demands that he withdraw from Kosovo. It might happen if, as British officials were suggesting, increasingly aggressive targeting by Nato was taking its toll.

A second scenario was the "degradation" of Serbian forces in Kosovo by Nato, allowing the KLA to gain the upper hand in its war against rule from Belgrade.

The third outcome that Clinton is contining to explore is a diplomatic solution involving the Russians. Early last week he held a 40-minute telephone conversation with President Boris Yeltsin. It was far more cordial than one at the start of the conflict when the Russian leader ranted about American "aggression" in the Balkans.

On Wednesday, Viktor Chernomyrdin, the former prime minister appointed by Yeltsin to try to mediate a solution, flew to meet Milosevic. This raised fears in American and British officials that he might travel to Washington from Belgrade clutching a peace appeal from Milosevic that would divide the alliance.

In the end, the Milosevic "concession" turned out to be nothing of the sort. He was proposing something that had already been dismissed by Nato as absurd: an international security force without guns.

Yet in the hope of encouraging Russian attempts at mediation, the alliance softened its conditions. In a 17-point communiqué, the allies said they were prepared to end airstrikes once Milosevic had begun - rather than completed - a withdrawal of troops from Kosovo.

It will be a fine 50th birthday present for Nato if Moscow, the old enemy, solves its Balkan problem. Clinton has flattered Yeltsin by acknowledging that Russia is the only recognised power which can act as an influential mediator. For his part, the Russian president is said to have become increasingly frustrated with Milosevic's intransigence.

At a reception for Russian journalists at the Kremlin last week, he had little to say about Slav brotherhood. "He spoke with little sympathy about Milosevic," said Irina Petrovskaya, a television journalist who attended the ceremony. "He insisted that it was necessary to negotiate with him but then added that 'we want to embrace him as tightly as possible' - gesturing as if he were strangling him."

THE WAR SO FAR

DURATION: 32 days

ATTACKS: More than 2,700 strikes on 500 target areas, using 700 aircraft; 9,800 sorties flown, on average 320 a day

NATO LOSSES: 1 F117-A Nighthawk stealth fighter, 1 Hunter reconnaissance drone, 2 German reconnaissance drones

SERBIAN LOSSES: Seven of Serbia's 15 MiG 29s destroyed, as well as 12 of its MiG 21s, 10 ground attack Super Galebs and nine MI9 helicopters. About 30% of its surface-to-air missile capability and 10-20% of its tanks and armoured vehicles
destroyed. Ten important bridges and the two rail routes to Kosovo hit

SERBIAN CASUALTIES: Yugoslavia claims 517 dead and 4,500 injured. Albanian casualties: 60 ethnic Albanians reported killed in Celina, 50 in Pec, 53 in Orahovac and 34 in Veliska. Nato estimates 3,500 killed in Kosovo. Yugoslavs claims 65 died in Nato's attack on civilian convoys

NATO FORCES DEPLOYED: Peacekeeping force of 12,400 in Macedonia. British contingent will rise to 6,800 with second element of the 4th Armoured Brigade; 4,000 Nato troops in Albania for humanitarian operations plus 5,000 American infantry with tanks and Apache ground-attack helicopters

Naval forces: US battle group of one cruiser, three destroyers and an escort; carrier battle group with USS Roosevelt aircraft carrier, two cruisers and a frigate; amphibious landing ships and submarines. British ships include aircraft carrier HMS Invincible and the nuclear submarine HMS Splendid

COST OF WAR: Missiles and bombs: £280m. Air support operation: £350m. Nato forces on the ground: £45m for peacekeeping force in Macedonia. Humanitarian operation: £400m

TOTAL: Estimated costs for humanitarian assistance and the military operation (including support) has reached £1.1bn