The news of the Israeli invasion of Gaza comes, alas, as no surprise. The nominal ceasefire, which expired on December 19, was always less than scrupulously observed. Ehud Barak repeatedly said that it was unlikely to last. The request from Israel for Hamas to desist from rocket fire into Ashkelon and Sderot is a reasonable one. A response of some kind to the resumption of mortar fire was inevitable.

In the event, the Israeli army is now fighting Hamas in the attempt to split the strip into three sections. If successful, this would have the effect of cutting off the supply lines into Gaza City from the south. To add to the toll from the bombing, 30 Israeli troops have been injured, two of them seriously. Nineteen Palestinian fighters have been killed. The wonder is not, unfortunately, that this conflict has broken out. It is that the world has shown itself so poorly prepared for it.

The performance of the European Union (EU) has been especially lamentable. Here was an opportunity for the EU to take a diplomatic lead. The interregnum in the US, where the serving President is seeing out his time but his successor is still 15 days from inauguration, created a diplomatic vacuum. Hostilities in Gaza demanded a mature and united diplomatic response. But behind the perfunctory call for a ceasefire issued on Saturday, what it saw instead was an unseemly squabble.

The Czechs, the leaders of the official EU diplomatic visit, opened the confusion by calling Israel's move “defensive”, before rapidly withdrawing the remark. The Swedish Foreign Minister, Carl Bildt, a member of the EU mission, was less mealy-mouthed. He criticised Israel unequivocally for choosing to “dramatically escalate” the crisis. France, which is about to relinquish the EU presidency, called for a ceasefire as Presdient Sarkozy prepared to depart for Jerusalem on the first stage of a personal diplomatic mission that will take in four countries over as many days. Meanwhile, his Foreign Minister, Bernard Kouchner, will remain with the bickering Czechs and Swedes in the EU mission. Gordon Brown called for an immediate ceasefire. The Dutch Prime Minister Jan Peter Balkenende said Israel could not be condemned as long as Hamas was firing rockets.

There is nothing dishonourable in countries disagreeing over such a conflict. But these outbreaks of national candour do threaten to make a mockery of the EU mission that is on its way to Jerusalem to meet the Israeli President Shimon Peres and the Prime Minister Ehud Olmert. From there, the EU team will proceed to Ramallah to meet the Palestinian President Mahmud Abbas, joined, for this meeting, by Mr Sarkozy.

The chances of success are not high and so the attention of the world will pass to Mr Obama, whose presidency will begin in a shadow cast by Gaza. In any conflict, of course, the protagonists hold the key to cessation. There can be no durable solution as long as Hamas refuses to recognise the right of Israel to exist. Though it is clear that the mortar attacks must stop, Israel might reflect on whether helping to relieve the manifest disaster of poverty and malnutrition in Palestine is not a quicker way to peaceful co-existence.

But other nations can help if they are now prepared to match words with deeds. Sonorous displays of outrage are all very well but what Gaza really needs is for the United Nations Security Council to agree with Israel a timetable for withdrawal. This should be done on the basis that UN monitors will be provided to ensure that the missiles abate and that replacement weapons are not smuggled across the borders. An accommodation in the region will be difficult, as it always is, but it is not impossible. It will, however, demand better leadership, from the protagonists and from everybody else, before this is remotely likely.