Refugees will not return without UN police to prevent ethnic cleansing

America isn't about to quit Bosnia altogether. US officials were at pains to stress yesterday that the 2,500 or so American troops serving with the S-For international peacekeeping force are going nowhere, despite Washington's veto of a Security Council resolution renewing the UN's mandate in Bosnia.

What is at immediate risk of closing down, possibly within days, is the UN police mission in Bosnia. This does not make the diplomatic brinkmanship in New York any less dangerous for the people of Bosnia.

For tens of thousands of refugees returning to their homes after the war, the UN police are the one guarantee of their safety, according to Michael Doyle of the International Crisis Group think-tank's Sarajevo office.

For the first time since the war ended in 1995, refugees who fled their homes during the fighting have begun to return in substantial numbers – tens of thousands in the past year.

Bosnian Muslims or Croats returning to areas that are now in the Bosnian Serb entity, or vice versa, are in grave danger of violence from the local majority.

That was underlined in May last year, when a mob of thousands of Serbs attacked Muslims trying to attend a ceremony to mark the rebuilding of a mosque destroyed in the war in the Bosnian Serb capital of Banja Luka. The Serbs besieged the Muslims in a local building, and set loose a pig on the mosque site. Local police forces have little interest in protecting ethnic minorities.

Bosnia is also an important conduit for smuggling of all sorts, from drugs and cigarettes to the European slave trade – the buying and selling of women for prostitution.

With corruption endemic in the underpaid local police forces, the UN police play a vital role in rescuing trafficked women and prosecuting the smugglers. It is no surprise that Europe is scrambling to fill the gap that would be left by the UN police – prostitutes aren't the only people smuggled through Bosnia, a route for illegal immigration into western Europe.

The legalistic justification for the American troops in Bosnia to stay on is that S-For's mandate comes from the Dayton accords that ended the war in Bosnia, not the Security Council. The real explanation is more probably that the US has its own reasons for wanting to stay – principally, fears that al-Qa'ida may be operating in the country.

Several Islamic charities involved in reconstruction efforts have been raided on suspicions of links to al-Qa'ida. In January, six Algerians living in Bosnia were arrested and handed over to the US. There are fears that some of the mujahideen – foreign Muslim volunteers who fought in the Bosnian war and stayed on – may be members of al-Qa'ida.

On top of that, Washington wants the other international court, the tribunal for the former Yugoslavia, to wrap up its trials of indicted Bosnian war criminals as soon as possible, and has been pushing S-For to track down fugitive indictees and arrest them.

Although the force has so far failed to get its hands on the two big fish, Radovan Karadzic and Ratko Mladic, it has been pulling in the small fry in droves of late.

Despite US assurances over S-For, there were dire warnings yesterday that the American veto on the UN mission in Bosnia could damage peacekeeping around the world.

Next to go, according to Carl Bildt, a former high representative in Bosnia, could be the UN mission in Kosovo. There an international presence is arguably more needed than in Bosnia, because the fighting ended more recently there – and because of the Kosovo Albanians' involvement in setting off Macedonia's near civil war last year.

Some argue that one positive effect of the whole row could be a wake-up call to Bosnians that it is time to take charge of their own destiny. Six and a half years after the end of the war, the country is going nowhere. Its economy is virtually non-existent, and an international presence is still needed to keep the three communities from each other's throats.