Most Americans will be unaware that the United States will soon be marking half a century of active involvement in the Middle East.

From the Israeli perspective, the close ties with the United States are a source of comfort and optimism

The Suez crisis of 1956, when Britain suffered political humiliation as it was forced to abandon its military campaign against President Nasser's Egypt, marked the end of a long chapter.

As Britain quietly withdrew from the region, the United States became the dominant outside player there.

Subsequent events have served to strengthen that dominance.

Defending the West

In the 1950s and 60s Washington viewed the Middle East through the prism of the Cold War politics of the day.

Sadat was pivotal in transforming Arab relations with Washington

While American oil companies were becoming established in Saudi Arabia and the Gulf region, US politicians and diplomats looked to Israel as a bulwark against communism and a key defender of Western interests.

Egypt and Syria, each with close ties with the Soviet Union, were regarded as threats to those interests.

The decision in 1972 by President Gamal Abdel Nasser's successor, Anwar Sadat, to expel Soviet advisors from Egypt opened the door to US influence.

After the 1973 Middle East war, US Secretary of State Henry Kissinger began many rounds of shuttle diplomacy that resulted in Israeli-Egyptian disengagement agreements in the Sinai desert.

US diplomacy has been at work in the region, to a greater or lesser extent, ever since.

Camp David

With one eye on the need to maintain stability in the Middle East because of the West's dependence on Arab oil, US administrations have explored various avenues in their search for a settlement of the Arab-Israeli conflict.

President Jimmy Carter hoped that the Camp David agreements that he brokered ahead of the signing of the Egypt-Israel peace treaty of 1979 would pave the way for a wider settlement.

But the Palestinians, resentful that their future was being negotiated on their behalf, rejected the offer of limited autonomy.

The next big opportunity for US diplomacy came in the wake of the 1991 Gulf war.

The Arabs recognise that the United States is the only power with political and economic leverage over Israel

With the Palestinians facing political and financial ostracism from their erstwhile backers in the Gulf, the PLO leader, Yasser Arafat, found himself with other Middle Eastern leaders at the Madrid conference of October 1991 - the moment when the current peace initiative was launched.

The Soviet Union was a co-sponsor of the Madrid conference, along with the United States.

But the subsequent collapse of the Soviet Union left the United States as the sole superpower and the sole major player in the Middle East arena.

This fact is a source of both optimism and pessimism for the various interested parties in the Middle East conflict.

The Arabs recognise that the United States is the only power with political and economic leverage over Israel.

The only hope, therefore, that Israel might be pressured into abiding by UN Security Council resolutions and pulling out of occupied Arab land lies with Washington.

Arab despair

At the same time, though, the Arabs despair at what they regard as blatant pro-Israeli bias in US policies, leaving successive US administrations unfit to act as honest brokers in the conflict.

Carter oversaw the first ever peace deal between Israel and an Arab state

From the Israeli perspective, the close ties with the United States are a source of comfort and optimism.

Despite a few periods of strained relations when Israeli governments have had to bow to US demands, there is an underlying confidence that no US administration would take steps that might cut across the interests of the Jewish state.

Because of the importance of the US-Israeli relationship - which is influenced in no small measure by the need for successive US presidents to keep the support of the Jewish lobby in America - the United States is not in a position to step in and impose a settlement.

The Israeli occupation of Arab land is viewed quite differently from the Iraqi occupation of Kuwait - as Arabs are quick to point out when they accuse Washington of operating by two sets of standards.

So, with little chance of the character of the politics behind US diplomacy changing, only a seasoned optimist would predict a comprehensive Middle East peace deal being achieved ahead of the 50th anniversary of US involvement in the region in 2006.