GEORGE BUSH flew in to a fanfare of bugles and cynicism at the start of his tour of the Middle East this week. The cynicism, it must be said, is not misplaced. Although he said in Jerusalem that he detected “a new opportunity for peace”, he has waited too long to make his first visit as president to Israel and the Palestinian territories. Even if he did everything right in his final year, he does not have time to realise his “vision” of a free Palestine alongside an Israel at peace with its neighbours.

Two things make that task look impossible. The first is the gap, no less wide for being so familiar, on the core issues. Ehud Olmert and Mahmoud Abbas are “moderates”. But although Mr Bush has persuaded them to talk about the ownership of Jerusalem, the borders of the putative Palestine and the fate of the Palestinian refugees, they remain far apart. Mr Olmert expects Israel to keep much of the dense band of settlements it has planted on the Arab side of the pre-1967 armistice line. He also insists that the logic of two states rules out any right which the Palestinian refugees of many decades ago claim to return to former homes in what has long been Israel. Mr Abbas will accept only tiny modifications to the pre-1967 border and still upholds the refugees' demand to go back.

The second, newer, obstacle to peace is that the Palestinian movement has split in half. With the Gaza Strip and its 1.5m inhabitants now under the control of Hamas, which is in turn under international siege, Mr Abbas can speak only for the West Bank, where more Palestinians live but over which his ramshackle Palestinian Authority exercises only the feeblest control. He, the Israelis and Mr Bush all know that until Hamas comes to accept the permanence of Israel and is somehow brought into the negotiations, no two-state solution can be made to stick. Indeed, much more likely than peace in Mr Bush's final year is an ugly new war, if the Palestinian rockets fired every day from Gaza eventually goad Mr Olmert into sending Israel's army to re-occupy some or all of the strip.

But if Mr Bush cannot achieve a breakthrough on his watch he can still do some things, at both a grand level and in detail, to bring peace closer and so make it less difficult for whoever takes his place in the White House to clinch the final deal.

The grand thing Mr Bush can do is to stop saying, as he did in Annapolis last November, that it is for Messrs Olmert and Abbas and nobody else to hammer out a two-state deal. On their own, with ideologues breathing down their respective necks, they do not and probably dare not agree. So America needs to promote a plan of its own. This does not require much effort. As it happens, most governments, as well as most ordinary Palestinians and Israelis, have a shrewd idea of the needed compromises: land swaps to make up for the few bits of the West Bank Israel will be allowed to keep, a shared Jerusalem, compensation but no general return for the refugees, except to the new state in the West Bank and Gaza. Mr Bush's refusal to say all this loud and clear is odd. For example, Mr Olmert is willing to enrage Israel's right by talking about the need to share Jerusalem. Why can't Mr Bush? His answer is that an imposed plan wouldn't stick. But the moderates in Israel can get nowhere if the superpower won't take their side.

Please try to focus

To counter the cynics, Mr Bush will need to show sustained attention to the details as well. This does not guarantee success, as Bill Clinton discovered at Camp David in his last, frenetic peacemaking months as president. But without close attention, the conflict in Palestine has a habit of either stagnating or getting worse. To date, Mr Bush has always seemed distracted: first by Iraq and now by a desire to build a regional alliance against Iran. It is time for him to roll up his sleeves and concentrate. In the coming months, for example, he should insist on Israel implementing its long-promised West Bank settlement freeze, not just shrug helplessly when it doesn't.

Neither grand plans nor vigilant policing of interim agreements will end this tangle at a stroke. But only genuine, robust American engagement will revive some hope and steer Palestinians and Israelis alike towards the hard choices they need to make. Like Moses, Mr Bush can still point the way towards the Promised Land, even if it falls to another to finish the job.