When the US led the war against Iraq in 1990, it sought to include the largest possible number of Arab countries in its coalition. To maintain the alliance during the war, the US leaned on Israel not to respond to Iraqi Scud missile attacks; after the war, it pressed Israel to join Arabs in the 1991 Madrid peace conference that launched the now-beleaguered peace process.

A decade later, the US is trying to build a broad partnership to fight a new and more complex type of war. The objective is far more important than in the Gulf war - not simply to protect a Gulf ally or secure US access to oil, but to ensure the security of American citizens.

Again, the US needs assistance from Arab states, home to cells linked to the terrorist Osama bin Laden and his financial network. And, as in the days of the Gulf war, the Palestinians are waging an intifada, or uprising. So a settlement of the Arab-Israeli conflict, which governments say feeds anti-American sentiment, is the Arabs' highest priority.

"This is at least as dramatic as the Gulf war and we need the Arabs even more," says Philip Gordon, senior fellow in foreign policy studies at the Brookings Institution. "Last time the Arabs were scared and they had their own interests at stake. Now we are cornered and we may need to pay more."

US pressure on Israel - not only on Palestinians - last week to declare a new ceasefire has underlined Washington's determination to prevent Middle East violence from threatening its coalition.

But the prospects of this attitude translating into a longer-term policy that reverses the Bush administration's hands-off approach and moderates its support for Israel are constrained by the dynamics of the violence and Washington's reluctance to be seen as responding to terrorist actions.

"There is a worry about rewarding terrorism... and an unwillingness to acknowledge that the peace process has anything to do with this," says Mr Gordon. "But although many people deny it, the administration understands that Arab regimes know the peace process matters, and that they cannot give the US help without having something on the Palestinian conflict."

Both Arabs and Israelis are conscious that the September 11 attacks could change the dynamics of the Middle East conflict.

Yassir Arafat, the Palestinian leader, whose support for Iraq in the Gulf war undermined his international credibility, has learned his lesson. So while some Palestinians were seen celebrating in the streets, Mr Arafat was desperate to show that he was on the US side.

Lebanon and Syria too have adopted positions that have pleased Washington. But they also want the US to distinguish between global terrorist groups such as Mr bin Laden's and organisations that are considered resistance movements against Israeli occupation.

"An international effort to destroy the infrastructure and the network of the terrorists in the world is needed. But fighting terrorism is not a regular war and you have to also eliminate the political reasons for this," says Rafiq Hariri, Lebanese prime minister. "If the Americans don't put enough effort into solving the issues in the Middle East, they will face incredible problems."

Ariel Sharon, Israeli prime minister, appears concerned about a possible shift in US attitudes. He has told the US that Israel could not be made to pay the price of forming the coalition against terrorism, or to be asked to treat terrorism directed against it differently from that directed at others.

US policy, say analysts, will partly depend on Israel's willingness to listen to Washington and, more importantly, on Mr Arafat's ability to rein in radical groups at a time when his authority has been eroded.

"Arafat has zero credibility in Washington at this point," says Geoffrey Kemp, director of regional strategic programmes at the Nixon Center in Washington. "He's got to convince people that he wants an end to violence and that he's prepared to negotiate a deal. Then Sharon will come under enormous pressure. He does not have a long-term strategy any more than Arafat does - but Sharon is in good graces in the eyes of the US."