President Bush arrives in Israel today at the start of one of the longest, most challenging and potentially most significant overseas tours of his presidency. He will be brought face to face with four of the issues that have dominated much of his time in office: the Israel-Palestinian conflict, Iraq, stability in the Gulf and the threat posed by Iran to regional security. Success in any of these areas would be important. Mr Bush clearly intends to devote much of his time and energy in his final year to the region, not only because there are issues where his leverage remains crucial but because, like other presidents at the end of their term, achievement in the Middle East would be an important way to burnish his legacy.

It is a little unfortunate, therefore, that the White House has planned the trip the wrong way round. It would have been better, and politically more productive, to have begun in the Gulf before arriving in Israel and the Palestinian territories. A presidential visit to Israel is long overdue: a sitting president has not visited America's key ally in the Middle East for nine years, and in office Mr Bush has been neither to Israel nor to Saudi Arabia, an equally important political and economic partner. But even the White House will admit that little has been achieved since the Annapolis peace conference six weeks ago. Indeed, Mr Bush arrives at a time when the security situation is tenser than it has been for months. The Israeli Government is under strong pressure to respond to the barrage of rocket attacks from Gaza with new airstrikes or a full-scale military incursion. New rocket attacks across the Lebanon border threaten to reignite conflict in the north. And a recent Israeli raid into Nablus has inflamed tensions on the West Bank.

By contrast, Mr Bush will receive a warm welcome in the Gulf, where he will hold talks with four governments that count themselves as staunch US allies, eager to cement ties with important, if largely symbolic, visits. In Kuwait, Mr Bush will be able to give reassurance that US policy in Iraq remains steadfast, that the level of violence, despite recent suicide bombings, is well below the level before the surge and that Sunni-Shia tensions can be contained. In Bahrain he will tell a nervous government that the Sixth Fleet is robustly ready to respond to new Iranian provocations. And in Saudi Arabia, his first visit should go a long way to defusing the suspicions and misunderstandings that have clouded a strategic relationship for the past six years.

In addition, throughout the Gulf Mr Bush will deliver two important messages. First, he will insist that the US fully understands the regional fears of aggressive Iranian nationalism and will continue the pressure on Tehran to change its behaviour. And secondly, he will call for greater Arab support, financial as well as political, for the US-brokered attempt to set up a viable Palestinian state within a year - the target date agreed at Annapolis. Sadly, that still looks a long way off, as does any reconciliation between President Abbas and his Hamas enemies in Gaza. It would have been useful to have brought such support from the Gulf states to the talks in Israel and the Palestinian territories. But even if Mr Bush's first visit does not produce a breakthrough, it signals a new and highly welcome White House determination to seek peace between the enemies in the Middle East.