'Ariel Sharon promised peace with security and has decidedly failed to deliver either...'

Despite attempts to find a settlement in the Israeli-Palestinian conflict, the situation has gone from bad to worse. Avi Shlaim argues that it is time for the United States to impose a solution - if only to save Israel from itself.

There are striking parallels between the Gulf war and the war in Afghanistan: both were given the broader agenda of freeing the world from international terrorism; some of the key US positions today are held by Gulf war veterans; in both conflicts the American president sought to build a broad international coalition to confront the aggressor and Israel was kept at arm's length to preserve it; and in both cases a link was quickly established between the conflict at hand and the Palestine problem.

In 1990, Saddam Hussein pioneered the concept of "linkage" by making Iraq's withdrawal from Kuwait conditional on Israel's withdrawal from all the Arab lands that it occupied in 1967. President George Bush rejected the proposal but he could not, without exposing himself to the charge of double standards, insist that Iraq should comply immediately and unconditionally with United Nations orders to withdraw from Kuwait without accepting that Israel should be made to comply with similar UN resolutions.

After the Gulf war, the Bush administration came up with a five-point plan for the future of the Middle East, which included a settlement of the Arab-Israeli conflict - the only point to receive sustained attention.

The American-sponsored peace process was launched with the Madrid conference in October 1991. In his opening speech, President Bush was faultlessly even-handed, pledging to work for a settlement based on security for Israel and justice for the Palestinians.

But as long as Itzhak Shamir, the leader of the rightwing Likud party, remained in power, no real progress could be achieved. Bush failed to deliver on his pledge "to push the Israelis into a solution", although he contributed to Shamir's replacement by Itzhak Rabin in June 1992. But the bruising battle was also a factor in his own defeat later that year by Bill Clinton.

Clinton abruptly reversed the even-handed policy of his predecessor and replaced it with an "Israel-first" policy reminiscent of the Reagan administration. In effect, the US abdicated its independent role as the manager of the peace process. A breakthrough occurred in Oslo only in September 1993. An accord was negotiated directly between Israel and the Palestine Liberation Organisation without America's help or knowledge. Israel recognised the PLO as the representative of the Palestinian people and the PLO renounced terrorism.

Clinton served essentially as the master of ceremonies when the accord was signed. He did recognise, however, the need for an active American role in supporting the experiment in Palestinian self-government. But while Israel continued to receive $3 billion (£2.07 billion) a year and extra funds to finance its withdrawal from Gaza and Jericho, only modest "seed money" was advanced to the Palestinian Authority.

The rise to power in May 1996 of a Likud government headed by Binyamin Netanyahu, a bitter opponent of the Oslo accord, who is committed to the old vision of a Greater Israel, dealt a heavy blow to the peace process.

The electoral victory of Ehud Barak in May 1999 promised a fresh start, but Barak was a hopelessly incompetent domestic politician and maladroit diplomat. Seeing Syria, a military power, as more important that the Palestinians, he focused on an agreement with it first and turned to the Palestinians only after this approach failed. Throughout this period, Clinton remained solidly behind Barak and made no attempt to play an independent role.

The critical point in the Israeli-Palestinian final-status negotiations was reached at the Camp David summit in July 2000. Israelis and Palestinians disagree about the causes of failure, blaming each other. But why did Clinton put all the blame on Arafat? The answer suggested in a first-hand account by Robert Malley, special assistant on Arab-Israeli affairs, and Hussein Agha, a Palestinian expert, is that Camp David exemplified for Clinton the contrast between Barak's political courage and Arafat's political passivity. But they also point to the complex and often contradictory roles that the US played at the summit: as principal broker of the putative peace deal; as guardian of the peace process; as Israel's strategic ally; and as its cultural and political partner. It is difficult to avoid the conclusion that Clinton's commitment to Israel undermined his credibility as an honest broker and was therefore one of the factors that contributed to the collapse of the Camp David summit.

Clinton himself seems to have drawn the right lessons. On December 23 2000, he presented a detailed plan for the resolution of the Israeli-Palestinian dispute that included the vision of an independent Palestinian state over the whole of Gaza and 94 to 96 per cent of the West Bank. Considerable progress was made on the basis of these proposals in Taba in January 2001, before time ran out on two of the main actors. Clinton was replaced by George W. Bush and Barak by Ariel Sharon.

Unlike Clinton, Bush adopted a "hands-off" attitude to the peace process. He also cold-shouldered the Palestinian leader and established surprisingly warm relations with the rightwing Israeli leader and seemed to have sympathy for his portrayal of Arafat as a terrorist.

One might have expected Bush Jr to resume the even-handed policy of his father towards Arabs and Israelis. In fact, he ended up by returning to the blatantly, and even blindly, pro-Israeli policy that had prevailed under Ronald Reagan.

The terrorist attack on America on September 11 violently shook the kaleidoscope of world politics. Many Israelis hoped it would engender greater sympathy and support in America for their own war against Palestinian militants. But attempts to demonise Arafat backfired. While Israel was firmly excluded from the emergent anti-terror coalition, some of its enemies were being considered for membership, and Hizbullah, Hamas and Islamic Jihad were conspicuous in their absence from the list of terrorist organisations that had their assets frozen by Congress.

Israel felt that it was being treated almost as a pariah. But worse was to come. Two weeks after September 1l, Bush issued the strongest statement yet endorsing an independent Palestinian state with East Jerusalem as its capital. The Bush administration's plan envisaged the handing back of nearly all the West Bank to Palestinian control. Sharon reacted with an astonishing outburst of anger. He warned Bush not to repeat the mistake of Neville Chamberlain in 1938 of trying to appease Nazi Germany by offering Hitler part of Czechoslovakia. The official American response reflected extreme displeasure. Although Sharon expressed regret for provoking this public row, his allegation of appeasement and treachery continued to rankle.

His reaction to the revenge killing of tourism minister Rehavam Ze'evi by the Popular Front for the Liberation of Palestine, in Jerusalem on October 17 - an order for the army to reoccupy six cities on the West Bank - deepened the crisis in relations with the US.

The US denounced the move in uncharacteristically blunt terms and called on Israel to quit the West Bank cities immediately and without conditions. Sharon rejected the demand in a remarkable display of defiance, but a gradual withdrawal from the West Bank cities was set in motion as he realised that September 11 would not allow him to redefine the rules of the Israeli-Palestinian game.

The pro-American Arab regimes viewed the escalation of violence in Palestine with mounting anguish and anxiety. They had been shamed and discredited in the eyes of their own people by their inability to help the Palestinians or to modify America's blatant partiality towards Israel. Osama bin Laden also played his part: in swearing that America would have no peace until Palestine was free, he succeeded in setting the agenda for Arab demands on Palestine.

Then on March 29 this year, following a series of suicide bombings in Israeli towns, Israel launched a massive military incursion into West Bank towns and villages. The declared aim of "Operation Defensive Shield" is to destroy the infrastructure of terror. The champion of violent solutions, however, has a much bigger agenda: to sweep away the remnants of the Oslo accords; to destroy the Palestinian Authority; and to extinguish once and for all Palestinian aspirations to independence and statehood. The operation was pursued with savage brutality towards innocent people, and in complete disregard for international public opinion and for the Geneva Convention.

America came under strong pressure to rein in its client. In an apparent reversal of American policy a week after the invasion, President Bush called on Sharon to pull out his troops from the West Bank. Sharon brushed aside the call, insisting that they would stay for as long as necessary to complete their mission of uprooting the infrastructure of terror. Secretary of state Colin Powell was dispatched to the region to arrange a ceasefire. But a suicide bomb in Jerusalem led to another swing of the pendulum in American policy. Sharon was let off lightly, all the onus for ending the violence was put on Arafat, and Powell returned empty-handed to Washington.

For the majority of Arabs and Muslims, Palestine remains the central issue in their attitude towards America's "war on terror". And the dominant perception so far has been one of American double standards.

In my view, the only solution to the Israeli-Palestinian situation is an externally imposed one, given the inability of the two sides to reach a solution on their own and the failure of the US policy of supporting Israel to bring it to the negotiating table.

An externally imposed solution need not be brutal. Indeed, if it is, it will backfire. The key to progress is to bring about a change in Israeli public opinion in favour of ending the occupation and conceding to the Palestinians the right to genuine national self-determination.

Improbable as it may look today, such a change is not inconceivable. The Israeli public has never been as resistant to the idea of Palestinian statehood as the politicians of the right. At the last elections, Sharon promised peace with security and has decidedly failed to deliver either. Today, Sharon does not have a plan with the remotest chance of being acceptable to the other side, and he knows it. Subject to the most intense pressure by his coalition partners, his main aim is survival and that precludes the option of voluntary withdrawal from the West Bank. So once again, as so often in the past, the peace process is held hostage to domestic Israeli politics.

Only the US can break the deadlock in Israeli politics. America's credentials as a friend are impeccable. Since 1967 it has given Israel more than $92 billion in aid. America should involve the UN, the European Union, Russia and its Arab allies in a concerted effort to generate internal pressure on Sharon to move forward on the political front, but its own leadership role is crucial. The key point to drive home is that America remains committed to Israel's security and welfare, and that the country's security will be enhanced rather than put at risk by ending the occupation of the West Bank and Gaza.

Arguably, America would be doing Sharon a favour by walking him into a peace deal against his ideological inclinations and many Israelis would be grateful for liberating them from the 35-year-old colonial venture that has so disastrously distorted the Zionist political project. In the end, it might be a question, as George Ball once put it in an article in Foreign Affairs , of how to save Israel from itself.

Avi Shlaim is professor of international relations at Oxford University and author of The Iron Wall : Israel and the Arab World (Penguin 2000). This is an edited version of an article in Worlds in Collision: Terror and the Future of Global Order , edited by Ken Booth and Tim Dunne, to be published by Palgrave Macmillan in June, £14.99.