Leading article: A trip that underlines the tragedy of Tony Blair

The Prime Minister has finally made the Middle East trip he first outlined to President Bush in July. In a way, to salvage some dignity, he had to. An open microphone at the G8 summit had revealed volumes about the Bush-Blair relationship. From the greeting "Yo, Blair!" to the round rejection of his offer to go to the Middle East, Tony Blair came across as the very junior partner in a joint enterprise. Thereafter, he had little choice but to go to the region on his own account.

By then, however, he had burnt yet another of his diplomatic boats. His failure to join European leaders in calling for an immediate ceasefire in Lebanon only reinforced the widespread view of Britain as a political appendage of Washington. It took an extraordinary letter from the British ambassador in Washington to convince Mr Blair to introduce some political distance between himself and Mr Bush.

The memory of this egregious misjudgement endures, and part of its price was the lukewarm reception Mr Blair was accorded at the headquarters of the Palestinian Authority in Ramallah and yesterday in Lebanon. Both meetings were also marked by street protests. Even behind closed doors, it seems that Mr Blair's capacity to achieve anything in the Middle East is now seriously constrained. In Ramallah, Mr Blair's proposal for a united Palestinian government that recognised Israel was rejected, only to re-emerge in a modified form yesterday, with the announcement that President Mahmoud Abbas and Hamas had reached agreement on a government of unity, if not on the recognition of Israel. It was a similar story in Beirut. A protest at the press conference diverted attention from Mr Blair's announcement of a £40m aid package.

Only in Israel was Mr Blair's official welcome as fulsome as he is used to. But street protests calling for the resignation of Ehud Olmert illustrated how far this was a meeting of two leaders who are on the way to becoming lame ducks in their respective countries. No wonder Downing Street was concerned to play down any expectation that the Prime Minister's trip would be able to break the present stalemate.

There was a time when Mr Blair could reasonably have hoped to make a personal contribution to peace in the Middle East. His close, and often enthusiastic, association with the Bush administration has put paid to that ambition. The first craven mistake was to ally himself with the United States for the war in Iraq. The latest was the delayed response to Israel's assault on Lebanon, which undid three years of painstaking efforts to separate himself from Mr Bush.

No wonder David Cameron yesterday sought to draw a line between a Conservative foreign policy and America's "neo-cons". No wonder, too, that he pledged to be "solid, not slavish" in relations with the United States. Mr Blair presents a living example of how an uncritical approach to the alliance has handicapped whole swaths of British foreign policy.

The irony is that recent developments in the Middle East have produced opportunities as well as catastrophe. Israel's confidence in military might as a solution is diminished, even as its need for secure borders has been proved. Lebanon has had to confront Hizbollah as a state within its state and Hizbollah itself has raised expectations among its supporters that will be hard to meet without government help. And a weakened Israel has a new interest in talking to the Palestinians.

There are real openings here that could be exploited to re-start the peace process. The tragedy for Mr Blair, and for British diplomacy, is that any claim he might have had to perform the role of honest broker is now lost irretrievably.