The Big Question: Can UN peacekeeping succeed in Lebanon, and does it work elsewhere?

Why are we asking this question now?

Because the UN Security Council has decided to expand the existing 2,000-strong UN force in south Lebanon to establish a buffer zone with Israel, free of Hizbollah fighters, in the hope of ensuring a sustainable ceasefire. Israeli troops who fought a 34-day war with Hizbollah would then withdraw from southern Lebanon, from where the Shia militia had fired increasingly powerful rockets against Israeli targets. Negotiators at UN headquarters are attempting to obtain pledges from troop-contributing countries for the expanded force of 15,000, to be led by France. But there remain questions about who exactly would disarm Hizbollah and whether the force's rules of engagement have held up troop commitments.

What is causing the delay?

No country wants its soldiers to become sitting ducks in the middle of somebody else's war. The UN resolution establishing the new force is a bit of a fudge because it asks UN soldiers to "accompany and support the Lebanese armed forces" in establishing the zone, which is to be "free of any armed personnel, assets and weapons".

This is all to do with respecting Lebanese sovereignty and ensuring that the foreign soldiers would not be seen as occupiers. However, Hizbollah has made it clear it has no intention of handing over its weapons to the 15,000 soldiers of the impotent Lebanese army. And the countries which have expressed an interest in joining the Lebanon force say it's certainly not their role to disarm Hizbollah. Hence the anxiety among European countries, such as France and Italy, about the wisdom of deployment.

The longer the uncertainty about the rules of engagement continues, the greater the danger of the war being rekindled. Kofi Annan, the UN secretary-general, has acknowledged that the UN's failures have stemmed from situations where peacekeepers have been deployed in places where there was no peace to keep.

What were the UN's failures?

Rwanda stands out as the biggest humiliation. In April 1994, as the genocide of almost 1 million minority Tutsis and moderate Hutus began, UN headquarters turned a deaf ear to the urgent appeals from the UN force commander in Rwanda, Roméo Dallaire, for reinforcements.

The ground had been prepared for the Rwanda failure by the débâcle in Somalia which led to America's retreat from international peacekeeping for several years. In Bosnia, the so-called UN Protection Force was humiliated by the capture of peacekeepers, while the massacre of 7,000 Muslims in the UN-protected "safe haven" of Srebrenica in 1995 has been a lasting scar on the reputation of the world body.

While the UN peacekeeping department - which from 1993 to 1996 was headed by Mr Annan - cannot escape the blame for these disasters, it is the nations on the UN Security Council that are responsible for setting up peacekeeping missions and negotiating the mandate. And past UN reports bear witness to the fact that in many cases where the UN was out-gunned and under-resourced, the UN secretary-general of the day had argued for many thousand more troops than were ever contributed by UN member states.

There must have been some successes?

Yes, but you have to dig deep into history to find them. The Korean war was the first, when UN member states acted collectively to repel aggression in June 1950 - thanks to the absence of the Russian delegate to the Security Council because his country was boycotting sessions at the time. The first Gulf War, in 1991, was ordered by the UN Security Council, which gave its blessing to a US-led coalition to reverse Saddam Hussein's invasion of Kuwait. But no blue helmets were involved, and in recent years, as we saw with Kosovo and the second Gulf War, the big powers have been too divided to join together to authorise military action.

The UN also does peace-building, where it moves in to pick up the pieces of countries smashed by war. In Kosovo, the UN was asked to run the Serbian province after the Nato bombing campaign. The UN performed the same role in East Timor. In Cambodia, it successfully carried out its mission to conduct elections and repatriate more than 360,000 refugees. But as also happened in Angola, the Cambodia mission was less successful in its disarmament phase, storing up trouble for the future.

How many UN peacekeeping missions are there?

Fifteen, at present, tying up a total 62,811 troops, but also 7,242 police and 2,671 military observers. The oldest is the UN Truce Supervision Organisation in the Middle East, set up in 1948 to monitor the cessation of hostilities in Palestine after the creation of the state of Israel. But in Haiti, UN soldiers have ended up killing the civilians they are there to help, while the reputation of UN peacekeeping missions in Africa has been tarnished by sexual abuse charges which fly in the face of Mr Annan's "zero-tolerance" policy.

Yesterday, the UN announced that it was investigating a suspected child prostitution ring involving its peacekeepers and government soldiers in the Democratic Republic of Congo. This is the latest in a series of sex scandals to hit the 17,000-strong mission, which was deployed in 1999 and which helped to organise last month's elections.

Will the UN succeed in Lebanon?

Frankly, no - unless Hizbollah and Israel have decided already they are fed up of war. Any UN mission is vulnerable because of the built-in delays in the chain of command, the bureaucracy and the delays in actually deploying forces on the ground. Normally, a UN force takes three months to gather and deploy, although UN officials are working to a tight schedule in the case of Lebanon, and are talking in terms of weeks, not months. But the commander of the UN Interim Force in Lebanon, French major-general Alain Pellegrini, said he thinks it will take a year before the full force of 15,000 can be in the field. That is too long to expect Israel and Hizbollah to refrain from fighting again.

Should the UN have its own standing army?

Yes...

* It would prevent the sort of delays that we have seen in the deployment of the Lebanon force

* It would remove the difficulties of depending on countries to volunteer troops and setting conditions for their deployment

* It would put peacekeeping back at the heart of the UN, which has been increasingly marginalised

No...

* Although envisaged in the original charter, no nations have ever been willing to consign permanently available forces to the UN

* There are already fears in the United States, in particular, about the UN moving towards being a 'world government'

* The problems of over-stretch would keep such a force dependent on member nations' willingness to pay