A second step would be to open the airport in the northern city of Tuzla to UN humanitarian aid flights so that more than 1 million civilians trapped in central Bosnia can receive food, medicine and shelter. The Tuzla region is the largest under the control of Muslim-led Bosnian government forces, but its airport is closed because it is within range of Serbian gunners.
A third step would be to relieve four other Muslim enclaves - Bihac in the north-west, and Gorazde, Srebrenica and Zepa in the east - that were designated UN-protected 'safe areas' last year along with Sarajevo and Tuzla. This would be coupled with efforts to end the Croatian blockade of Muslims in the southern city of Mostar.
A fourth step would be to restart negotiations on an overall Bosnian settlement, with the United States and Russia guiding the Muslims and Serbs respectively towards peace. The shape of such a settlement is still unclear, but in the event of Bosnia's de facto partition into Muslim, Serbian and Croatian areas the minimum aim would be to provide the Muslims with a viable territory. The maximum aim would be a loose, decentralised Bosnian state within its pre-war borders in which each national group has certain guaranteed rights.
Obstacles stand in the way of each proposed step. It is possible that Serbian forces around Sarajevo, buoyed by the arrival of friendly Russian peace-keepers, will refuse to lift the siege until an overall Bosnian settlement favourable to Serbian interests is reached. Since that could be years away, Sarajevo could in the meantime become a divided city like Berlin, Beirut or Nicosia.
President Bill Clinton said yesterday that he understood the fears expressed by Bosnian Muslim leaders that Serbian forces might redeploy their Sarajevo guns on other war fronts. 'We're quite concerned about that,' he said.
It also seems unlikely that Western countries will be able to reopen Tuzla airport, or exert pressure on other fronts, by repeating the threat of Nato air strikes against Serbian artillery. The threat may have played a part in securing the removal of Serbian heavy guns from around Sarajevo. But unless the West wants a serious confrontation with Russia, air attacks have been made almost unthinkable now that Moscow has intervened in the Bosnian crisis in an overtly pro-Serbian fashion. 'You won't solve the problem from the air,' said Lord Owen, the European peace mediator.
President Boris Yeltsin's spokesman, Vyacheslav Kostikov, portrayed Moscow's move in Sarajevo as a Russian triumph. 'It is not just that Russia has returned to the roots of its historical role in the Balkans and defended the Serbs, whose faith, culture and national spirit is close to us. Russia has firmly established the parameters of its influence in Europe and the world,' he told Interfax news agency.
However, the head of Croatia's parliament, Stipe Mesic, expressed concern at the Russian initiative. 'It's a terrible danger. Now they are capable of putting some kind of ring around every city and securing Serbian gains. It is important that Serbs get it into their heads that there won't be any Greater Serbia,' he told the Independent in London.
Mr Mesic proposed that Nato should deploy peace-keepers on roads, bridges and railways along the Bosnian-Serbian, Bosnian-
Croatian and Croatian-Serbian borders. 'This would return the world to its principles: no change of borders by force,' he said. Without adhering to such principles, the West would one day face the danger that countries such as Russia, Hungary and Albania would demand the right to expand their frontiers and incorporate all their compatriots in neighbouring states, he said.
Another requirement for a lasting peace is an end to the Muslim- Croat war in central and southern Bosnia. Mr Mesic said that the two sides had made some progress at talks in Germany since they now appreciated that the Serbs alone benefited from their war. 'Muslims and Croats have fought in the way that two wounded animals in the same corner fight,' he said.
US experts said that, by dwelling on the issue of Serbian guns around Sarajevo, Western public opinion had lost sight of the larger question of what sort of Bosnia should emerge from the war.
'The issue is establishing a Bosnia that is viable,' said Robert McFarlane, a former US national security adviser. 'As matters stand, if you withdraw all the weapons and leave the Muslims with this gerrymandered piece of terrain surrounded by Serbian and Croatian forces, it's just not viable. It will be only a matter of time before Bosnia is extinct.'