ISRAEL announced yesterday that it would mount a ground offensive against Hezbollah that might last 30 days. This is a spectacular rebuff to all the attempts in the United Nations to broker peace.

Does this mean that the UN has failed? Even more, that it is impotent and irrevelant in the world’s conflicts?

Those are inevitable accusations. The UN is an easy target, all the more because the criticisms are often justified. In this crisis its secretariat, headed by Kofi Annan, the Secretary-General, could have done more.

This crisis is also the result of the UN’s neglect of past problems: the disarming of Hezbollah, above all others. Unifil, the UN’s security force, and the UN Security Council have too often taken the easy way out.

But this crisis is proving hard to solve because of factors that cannot be blamed on the UN: Hezbollah’s new strength; its support from a resurgent Iran; and the US’s aggressive approach to militant Islam since 9/11.

A four-week conflict has alarmed the world, where other outbreaks of fighting have not, because it has begun to seem like a proxy war between those rival interests, with echoes of Central America during the Cold War. The paralysis in New York is a sign of that fundamental tension, not of the failings of the UN itself. At the very least, the UN provides a room in which they can meet and disagree. In the favoured phrase of Donald Rumsfeld, the US Secretary of Defence, that is not nothing.

Yesterday it looked as if the entire structure that France, the US and Britain had stitched together over the weekend had unravelled. The US and Israel showed little sign of backing down on their insistance that Israeli troops would stay in southern Lebanon until a multinational force arrived. This is unacceptable to the Lebanese Government and France.

Russia was offering “Plan B”, a pause in fighting to allow aid to get in, but that failed to meet Israeli demands that Hezbollah should have no chance to rearm. When President Chirac of France said that it would be immoral not to push for an immediate ceasefire, he was playing the blame game, at the US’s expense, at which point the seepage of goodwill became audible.

How much of this paralysis could the UN have avoided? Some Arab critics feel that the secretariat has leant towards the US position, and held back from calling for a ceasefire. They feel that it could have done more to develop contacts with Syria, Iran and Hezbollah and to bring in their views.

On the other hand, Annan’s reflexive response was to accuse Israel of apparently deliberate targeting when its airstrikes killed UN observers. He has backpedalled since then, and overall the secretariat appears even-handed.

Chronic neglect is a better charge to make against the UN and Unifil, its interim force in southern Lebanon. Unifil did not have a mandate to enforce the disarming of Hezbollah, as set out in Resolution 1559 in 2004. But it could have done far more to alert UN members to Hezbollah’s rearmament.

And the Security Council itself? It is the world’s pre-eminent organisation for resolving conflict so, on the face of things, it has failed. Yet in this crisis, that easy charge is unfair.

France and the US, both permanent members of the council, have managed to thrash out a lot of common ground. The US and Israel, France and the Lebanese Government (with the obvious exception of the Hezbollah members) all want the disarmament of Hezbollah to be part of the outcome.

The main difference is that the US, giving no ground in its fight against terrorism, sees this as more important than the immediate end of the “hot war”. (This is a point that Annan unhelpfully muddied by calling for a ceasefire and saying at the same time that the status quo before this conflict, including Hezbollah’s military capability, was unacceptable.)

But the heart of the problem is that Hezbollah, buoyed up with the adulation of the Arab world, may now be too strong to be disarmed, unless it agrees that this should happen. No diplomatic solution will be easy. That is a greater reflection of Iran’s new strength than of the UN’s weakness.

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