History is repeating itself in the Middle East. The challenge for the peacemakers is to ensure that it does not repeat itself too closely.

As when Yitzhak Rabin and Yasser Arafat shook hands on the Oslo peace accords at the White House six years ago this month, most people on both sides of the Israeli-Palestinian conflict are generally supportive of the latest attempt at reconciliation, summed up in the accord signed by Ehud Barak and Mr Arafat at Sharm al-Sheikh in Egypt on Saturday.

Now as then, the moderate Arab world, the European Community, the US and others are issuing messages of support and pledges of assistance.

There is talk, once more, of new eras, of windows of opportunity, of better futures for generations to come. And, again as six years ago, there is much earnest concern being expressed about the threat posed by the extremists, the opponents of compromise - and the obligation borne by all who sincerely hope for peace to work in partnership to frustrate them.

What nobody is yet acknowledging, not in public at least, is that last time around the opponents prevailed. They succeeded in stalling the bridge-building; if not confronted, they can succeed again.

In February 1994, West Bank Jewish settler Baruch Goldstein opened fire with round after round of ammunition in Hebron's Cave of the Patriarchs, bringing death indiscriminately to the ranks of innocent Palestinians kneeling in prayer. In November 1995, Yigal Amir fired just three bullets, at a carefully selected target, and killed Mr Rabin.

And throughout that same period, and beyond it, the suicide bombers of Hamas and Islamic Jihad carried out bombing after bombing after bombing on Israeli buses, in the markets, at the shopping centres, killing dozens of men, women and children.

The violence gnawed away at public confidence, on either side of the divide, in the viability of Israeli-Palestinian relations. The broad public support gave way to disillusion. Majority backing became majority scepticism, even majority opposition. Mr Arafat grew weaker and older.

Benjamin Netanyahu squeezed into power in the wake of four suicide bombings in the space of eight days in the spring of 1996. President Clinton found himself preoccupied with his own personal crises. Israel's nascent ties with the likes of Jordan and Morocco grew strained. Settlements expanded. Palestinian jobless totals grew. Hamas thrived.

Now the Middle East has a second chance. Mr Barak, the self-proclaimed successor to Mr Rabin, has renewed the "spirit of partnership", as US Secretary of State Madeleine Albright declared on Saturday night, "absent in recent years". Jordan's King Hussein, a crucial behind-the-scenes catalyst, has gone. But Mr Arafat, though looking ever frailer, has survived.

Again to quote Mrs Albright: "A great task has been completed, and an even larger one remains". The inescapable root disputes - over rival claims to Jerusalem, water allocation, refugee rights of return, the fate of the settlements, Palestinian statehood, et al - have yet to be tackled with any seriousness. The notion, as the Sharm deal provides, of reaching a framework for agreement on these issues by next February, and a full, final, permanent accord within a year from now, is manifestly absurd.

But missed deadlines will not destroy this second opportunity. Every deadline ever set so far has been missed. What will destroy it, what the peacemakers have to ensure does not destroy it, is more violence.

The portents are mixed. Already yesterday there were explosions in northern Israel, linked by Israeli police to Palestinian extremist groups. At the same time, though, Jordan has been cracking down on Hamas, and Syria appears to be reining in the rejectionist groups it hosts. But it is with Mr Barak and on Mr Arafat that the main challenge rests, a challenge that proved too onerous last time: to reach out to the skeptics and assuage their doubts, and to thwart those on the margins who will not be convinced.