JERUSALEM, June 16 – With the two Palestinian territories increasingly isolated from each other by a week of brutal warfare between rival factions, Israel and the United States seem agreed on a policy to treat them as separate entities to support Fatah in the West Bank and squeeze Hamas in the Gaza Strip.

The idea is to concentrate Western efforts and money on the occupied West Bank, which Palestinian President Mahmoud Abbas and his Fatah faction control, in an effort to make it the shining model of a new Palestine that will somehow bring Gaza, and the radical Islamic group Hamas, to terms.

As Ehud Olmert, the Israeli prime minister, who arrives in the United States on Sunday to meet with American officials, said, a Fatah government, shorn of Hamas, “can be a new opening.”

After the failure of the Palestinian unity government, Mr. Olmert said in an interview with The New York Times, “I suggest we look at things in a much more realistic manner and with less self-deceit.”

But like all seemingly elegant solutions in this region, this one has many pitfalls. It is entirely unclear whether Hamas would sit still during such an effort, whether Mr. Abbas would be willing to ignore the 1.5 million residents of Gaza or whether the separation strategy would gain the crucial support of the Arab world.

As Daniel Levy of the Century Foundation and the New America Foundation in Washington suggests, it’s hard to imagine how Mr. Abbas could accept the tax receipts Israel has been withholding from the Hamas government and use them only for West Bankers. The Palestinians in Gaza and the refugee diaspora would not stand for it, he says, and Fatah might lose more popularity than it gains.

Mr. Abbas is already under pressure from some Arab governments, in particular the Saudis, who mediated the national-unity government at Mecca, to take Hamas at its word and try to recreate a shared government.

In a speech on Friday to an emergency meeting of the Arab League, Foreign Minister Saud al-Faisal of Saudi Arabia said, “The Palestinians have come close to putting by themselves the last nail in the coffin of the Palestinian cause.”

But he added, “It would be best for our Palestinian brothers to return to their commitment to the Mecca agreement and work to carry it out.”

Both the United States and Israel are reeling from the rapid and ignominious collapse of Fatah in Gaza in recent days, despite significant injections of American political and military advice and aid.

There is no question that, if they are to survive, Mr. Abbas and Fatah need bolstering fast after the victory in Gaza of Hamas, which favors Israel’s destruction. The whole future of the two-state solution – an independent Palestine living in relative peace with an independent Israel – seems ever more at stake.

The United States and Israel are each searching for short- and medium-term responses to a collapse neither saw coming. Both want to limit the regional impact of the latest victory of radical Islam over Western-backed, secular forces. And both are worried about the impact on Egypt, which is trying to seal its border from Gazan refugees and where President Hosni Mubarak faces a serious internal challenge from the Muslim Brotherhood, the radical Islamist organization with which Hamas is affiliated.

Mr. Abbas and Fatah say they are committed to a two-state solution with Israel. Whatever his weaknesses, which are manifold, Mr. Abbas still has the legal authority as head of the Palestine Liberation Organization to negotiate with Israel.

There is even talk of pushing Israel to negotiate with Mr. Abbas to create a Palestinian state in provisional borders in much of the West Bank and East Jerusalem, with Gaza left for another time – a way to use the road-map peace plan President Bush endorsed. This idea was floated by a former Clinton Administration official, Martin Indyk, now director of the Saban Center for Middle East Policy at Brookings, in an opinion article published Friday in The Washington Post.

For Mr. Olmert and Israel, the policy of treating the two territories separately would also be a way to justify the continued sealing off of Gaza from the West Bank on security grounds, to prevent the transfer of military equipment and skill. And it would also take the pressure off Israel to lift security restrictions on Gaza crossing points or to move very quickly to withdraw more settlers and soldiers from the West Bank, let alone start negotiating with Hamas.

But it is highly unlikely that Mr. Abbas, elected as president of all Palestinians, will change his refusal to accept statehood in provisional borders, or abandon all Gazans, many of whom would vote for Fatah if given a chance, to their fate.

That means efforts to reach a shared political consensus will have to continue, because Hamas is clearly not going to go away.

There is another problem with the idea of creating a beautiful West Bank Palestine at relative peace with Israel and with fewer checkpoints and restrictions. Hamas and Islamic Jihad, though kept underground there because of the Israeli occupation, could produce havoc, Iraq style, with a few bombs and suicide bombers. That would put a quick end to any easing of Israeli security restrictions.

And Hamas may in turn make something of its new responsibilities in Gaza. Without what it considers the troublemakers of the Fatah security forces, some of whom had been engaging in crime and destabilizing acts, Hamas may very well bring a new security to the people of Gaza. And if the customs connection to Israel is broken, it may be able to work out a deal to ship goods in and out of Egypt and create some jobs.

Still, Gidi Grinstein, a former Israeli negotiator who runs the Reut Institute in Tel Aviv, said that with Hamas now confronted with real power and responsibility for the welfare and security of Gazans, “this may turn out to be a Pyrrhic victory for them,” since they always wanted to share such responsibility with Fatah.

Hamas, he said, is “more comfortable in the gray area where it addresses the needs of the population but not the requirements of power.” But Hamas may find that it needs to deal with Israel and the compromises of politics in ways that could bring it over time, as Yasir Arafat and Fatah were brought, closer to the space in which two adversaries can negotiate a peace.

http://www.nytimes.com/2007/06/17/world/middleeast/17assess.html?hp #