The US Secretary of State Condoleezza Rice has visited Israel/Palestine no fewer than 15 times in the past 15 months - and has virtually nothing to show for it. Her diplomacy has been an exercise in futility.

Far from contributing to a resolution of the conflict, she has unwittingly demonstrated America's striking loss of influence - not least with its Israeli ally. She has also not escaped personal humiliation.

Whenever she moans, as she did on her previous visits, about Israel's expanding colonies, Prime Minister Ehud Olmert promptly authorises the construction of more housing units - hardly waiting for her to take off from Ben Gurion airport. It is nothing less than a smack in the face, but she has always come back for more.

It is probable that no previous American Secretary of State has devoted so much time and effort to the Israeli-Palestinian conflict - to so little effect. Rice seems desperate to achieve some hint of progress, however meaningless, for President George W. Bush to hail on his forthcoming visit to attend Israel's 60th anniversary celebrations. But as the "moderate" Palestinian leader Mahmoud Abbas said gloomily after his recent meeting with Bush in Washington, "Frankly, so far nothing has been achieved". He is learning the painful lesson of placing his hopes on the United States.

Those with long memories will not resist comparing Rice's helplessness and ineptitude with James Baker's magisterial descents on the Middle East as he rounded up local states - including Syria and a highly reluctant Israel - for the Madrid Conference of 1991, which marked the launch of the peace process 17 years ago.

Why has Rice been so ineffective? The ultimate responsibility must, of course, rest with her boss, President Bush, who clearly has not given her the means or the authority to act decisively, largely because of his own poor grasp of the subject and because of the many influences on him - from Vice-President Dick Cheney, from Eliott Abrams, the neocon in charge of the Middle East at the National Security Council, and from the many Washington lobbies and think tanks committed to the Israeli cause. The time when the US was any sort of an honest broker has long since past.

The paradox is that while Bush professes to want an Israeli-Palestinian agreement by the end of the year, he is plainly unwilling to pressure Israel on any of the issues which could make it happen.

When Rice was asked by a reporter on her latest trip whether she would exercise pressure on Israel on the matter of the colonies, she answered that it was not a question of exercising pressure but of solving problems. But how she expects to achieve the latter without resorting to the former is truly baffling.

Free from any semblance of US pressure, Israel has continued the building of colonies on Palestinian land in the West Bank and East Jerusalem. It has failed to evacuate any of the more than 100 illegal West Bank outposts, halt lethal military incursions into Palestinian towns and villages, release any of the more than 10,000 Palestinian prisoners, or dismantle the more than 500 roadblocks that make Palestinian life a misery. Meanwhile, the siege of Gaza remains ruthlessly in place.

At the same time, the Bush administration has shamefully neglected the core issues of the conflict, such as Israel's final borders and those of a future Palestinian state; compensation or resettlement for the Palestinian refugees; and the fate of occupied Jerusalem. No Palestinian leader can sign an agreement with Israel which does not provide for Palestinian sovereignty over the Haram Al Sharif, or Temple Mount.

Apart from the constraints imposed by domestic forces at work on the Bush administration, there are more specific reasons for Rice's failure.

Fatal mistake

Her fatal mistake is that she has set her aims far too modestly. Instead of working for a comprehensive Arab-Israeli settlement - the one the whole region wants and desperately needs - she has put her effort into seeking an agreement between two tarnished and unrepresentative figures - Israel's Prime Minister Ehud Olmert, who is this week yet again facing serious charges of fraud, and Mahmoud Abbas, the hapless president of the nearly moribund Palestinian Authority. These limited aims are enough to doom Rice's efforts.

It takes no expert to understand that there can be no peace which excludes two major players - Syria, and the Islamic movement Hamas, which rules in Gaza. Yet Rice defends a policy which, instead of engaging with Syria, sanctions and seeks to isolate it, while treating Hamas, victor of the democratic Palestinian elections of January 2006, as a "terrorist" organisation.

Rice has even gone so far as to depict the men of Hamas as "proxy warriors for Iran" - a real howler in view of the movement's origins in the Muslim Brotherhood and its purely Palestinian objectives - and has accused it of "taking the Gaza population hostage" and of "building a terrorist infrastructure".

Instead of working for a reconciliation between Hamas and Mahmoud Abbas' Fatah - essential for any serious progress towards peace - she wants them to fight each other, still entertaining the Israeli illusion that Hamas can be subdued by brute force. She seems unaware that aping the language of Israel's security chiefs rules her out - and discredits the United States in Palestinian and Arab opinion - as an acceptable mediator.

More serious still is Rice's failure to outline a US vision of what an Israeli-Palestinian settlement would look like. Bush's lazy attitude is that it is up to the parties to make the deal. He clearly does not intend to present guidelines of his own for a solution of the conflict - not even "parameters" such as Bill Clinton advanced in the final weeks of his presidency. But such is the inequality between an all-powerful Israel and the battered, broken and divided Palestinians that there can be no hope of a settlement without a vigorous US input. To "leave it to the parties" is to guarantee failure.

The most extraordinary feature of Rice's diplomacy is that she is not seeking any sort of firm compact, or treaty, or commitment from both sides, enshrining clear undertakings and timelines, but rather a "shelf agreement", a poor creature hitherto unknown in the annals of peace-making.

What is a "shelf agreement"? As its name suggests, it is an agreement which can be put on the shelf until its signatories judge the time ripe to implement it - which is certainly not now and probably never.

Bush will be remembered for the tremendous damage he did to the Arab world and to the United States by his war in Iraq. It will take decades to repair the damage. At one time, there was a glimmer of hope that, aided by the faithful Condy, he might seek partially to redeem himself by being the architect of an Arab-Israeli settlement.

Bush spoke the words - he mentioned the objective of a "Palestinian state" - but, in the absence of resolute action, words alone cannot and will not do the job.