"There is no middle ground left after this," one envoy said. "Muddling through in the old way won't work, so either you apply force selectively or you pull the UN out altogether."
Like the six Nato attacks on Bosnian and Croatian Serb targets last year, the air strikes made little impact on the Bosnian Serbs' military strength. But the political repercussions of the attacks appear far-reaching.
The air raids provoked such a brutal response from the Bosnian Serb army, including a bombardment of Tuzla that killed 71 people, as well as the use of UN personnel as human shields, that Nato may have to strike again or risk looking impotent.
The White House spokes-man, Mike McCurry, yesterday reminded the Bosnian Serbs that hostage-taking would not deter new air attacks.
But there is a point beyond which Nato cannot intensify the conflict without causing a break with Russia. That would destroy the negotiating process, jeopardise more Bosnian Muslim lives and force the withdrawal of UN forces. Some Clinton administration officials accept this, and say it is important to replace bombing with negotiations, so that the UN does not have to leave Bosnia.
Hard though it is for Nato staff to accept, the lesson of last year's Nato attacks on the Bosnian Serbs was that it was Nato that blinked first. That has not changed, as the political conditions have never existed for a full-scale Nato assault on the Bosnian Serb forces of Radovan Karadzic and General Ratko Mladic.
Bosnia's Muslim Vice-President, Ejup Ganic, put his finger on the problem when, reacting to the Nato strikes, he said: "We want massive measures, because we believe that the Karadzic Serbs will only listen to massive response and will react positively only if massive response by Nato is exercised."
That response that will not be forthcoming. As Nato's Secretary-General, Willy Claes, pointed out: "There is no military solution, only a diplomatic solution."
The paradox for Nato is that, while it had little choice but to launch the air raids on Thursday and yesterday, the strikes seem likely in the long run to damage Nato's reputation, as there can be no effective follow- up. The Serbs have demonstrated that they can carry on shelling civilians and intimidating the UN.
Nato and UN commanders deemed the air strikes necessary because the credibility of the organisations had been badly dented this month. Wanton Bosnian Serb shelling of Sarajevo had killed 11 people and fully justified a military response. But the UN in Zagreb vetoed air strikes, making Nato look helpless.
Next time, Nato members, in particular the United States, were determined to rise to the challenge. It came in the form of the Bosnian Serbs' seizure of four heavy weapons from a UN weapons-collection site, and the Serbs' failure to meet a deadline for returning them.
However, if the subsequent remarks of President Bill Clinton and leading US officials are treated at face value, the Nato attacks did not achieve their goal. President Clinton said he hoped that Nato's action would "ease suffering in the region", although it clearly did not have that effect in Tuzla.
The Secretary of State, Warren Christopher, said: "We also hope it will persuade them to end violence and pursue appropriate settlements".
But the Bosnian Serb response was quite the opposite, while the Muslim- led Bosnian government appeared to see the use of force by Nato as an opportunity to take the war to the Serbs.
The chairman of the US joint chiefs of staff, General John Shalikashvili, said he hoped Nato's action would "bring people back to the negotiating table". But the response of General Mladic to the air strikes was to call the UN commander in Bosnia, General Rupert Smith, of Britain, demand an end to the attacks and slam the phone down.
Although the West's diplomacy in Bosnia has enjoyed few successes in three years of war, one moderately promising avenue of opportunity has been closed off since the air strikes.
This is the attempt to persuade Serbia's President, Slobodan Milosevic, to recognise Bosnia in its pre-war borders, thereby undercutting Mr Karadzic and General Mladic.
Mr Milosevic may still harbour a dream of Greater Serbia and may have tried to deceive international mediators when he discussed recognising Bosnia in return for an end to sanctions on rump Yugoslavia.
British and French officials insist that Mr Milosevic was serious and, was "80 or 90 per cent" on the way to taking the momentous step when his talks with a US envoy, Robert Frasure, broke down last Tuesday.
With this way forward now blocked, with the UN operation in serious danger and with Nato's options limited, it seems that the only predictable factor in the Bosnian equation is that the war will stretch on into a fourth winter.