President George W. Bush embarks this week on a trip to the Middle East that may determine how history judges his legacy. So far, it is safe to say that the judgment will be largely negative. Mr Bush’s foreign policy has undermined America’s global legitimacy, not to mention his own credibility. He has plunged the US into a protracted conflict in the Gulf region while neglecting the increasingly ominous al-Qaeda challenges in Afghanistan and Pakistan. Last, global public opinion has turned against the US.

But a great deal could change if Mr Bush could make happen what he has just predicted in an interview with an Israeli newspaper: “There will be a comprehensive peace signed by the end of this year” between the Israelis and the Palestinians. Indeed, such a peace would be a breakthrough of genuinely historic dimensions.

To deliver this, Mr Bush must accept that an Israeli-Palestinian accord will not come about by itself and that the Israelis and the Palestinians by themselves will not reach it. Neither side is ready to offer a genuine compromise. Each side waits for the other to make basic concessions while professing a devotion to peace. Each side finds refuge in myths that justify intransigence.

For the Israelis, the recently constructed wall on Palestinian lands provides the illusion of security, reinforced by the awareness that Israel is infinitely more powerful than the Palestinians. Why then should Israel begin by making concessions to the weaker?

The Palestinian myth is born out of weakness. It compels them to take refuge in history, in the illusion that time is on their side, that the Israelis – like the crusaders earlier – will eventually have to give in, especially when Muslim hostility drives America out of the Middle East. Why then should the Palestinians begin by making concessions to the currently stronger Israel?

With neither side capable of initiating a genuine give-and-take bargaining process, it is up to the US to do so. Mr Bush is the only one who can make this happen if he is serious about his prediction. The way to do it is to spell out the grand framework for a fair and enduring peace when he is in the Middle East, thereby breaking the logjam, and then leaving it to the parties to resolve the details. He should state that a fair peace must be based on the following four fundamental principles.

1. No right of return to the state of Israel for the Palestinian refugees: a bitter pill for the Palestinians but one they must digest, for the Israelis cannot be expected to commit national suicide for the sake of peace. Some compensation and acknowledgement of their suffering, however, should be part of the settlement. The international community, which needs peace in the Middle East, could pitch in.

2. The genuine sharing of Jerusalem, including a section of the old city and the mosque with the Golden Dome as part of the Palestinian capital: a bitter pill for the Israelis but one they must digest, for otherwise the peace will never be viewed by Palestinians and Arabs more generally as legitimate. Joint arrangements would have to be agreed to prevent the city from being split altogether and that could include a special regimen for the holy sites.

3. Mutually agreed changes to the 1967 lines, based on equitable territorial compensation for any adjustments, designed to include in Israel the main urban settlements located near the final frontiers; and the phased evacuation of Israeli settlers from the settlements that will be in the Palestinian state, with some Palestinian refugees perhaps then resettled in the new state.

4. A demilitarised Palestinian state, with some form of international security presence within it. Perhaps the US might consider a permanent US presence along the Jordan river as a form of security reassurance to the Israelis. That should address the Israeli sense of vulnerability without arousing Palestinian anger that some aspects of the Israeli occupation would persist even after the peace treaty.

A firm statement outlining the US view of an equitable peace along these lines would command instant global support. It would also enjoy significant support among Israelis and Palestinians (as indicated by public opinion polls) while breaking the negotiating stalemate between the two parties. Once momentum is generated it could even lead to peace this year.

In 2002 Mr Bush stated that he hoped to achieve a two-state solution by 2005. It is now 2008. Only the US can do it and that demands action from the president, not just more words.