It’s a grand occasion when a new Israeli prime minister makes an inaugural visit to Washington. He typically meets with the president, addresses a joint meeting of Congress, appears on plum television shows, talks to influential audiences, and consults privately with a range of leading figures. Personality, pomp, and substance mix together as the two heads of government establish a working relationship, the America-Israel bond is reconfirmed, and issues relating to the Arab-Israeli conflict are reviewed.

When Prime Minister Olmert arrives in a few days, the key policy issue will concern what he refers to as the “convergence plan,” a follow-up to the Gaza withdrawal of mid-2005 with a comparable but larger removal of Israeli soldiers and residents from the West Bank.

David Makovsky has pulled together the several components of this far-reaching plan in a recent Washington Institute for Near East Policy study, “Olmert’s Unilateral Option: An Early Assessment.” These include:

Israel’s security fence will serve as the baseline for a boundary with the West Bank, 92% of which will come under Palestinian Authority control. Israel will retain three residential blocs (Gush Etzion, Maale Adumim, and Ariel) with an estimated 193,000 Israeli civilians, but at least 60,000 Israeli civilians will be evacuated by 2010 from the West Bank, using force if necessary. Arab neighborhoods in Jerusalem will be incorporated in the West Bank, reducing that city’s Arab population by 140,000. Conspicuously, the plan does not address the future of Israel’s military presence.

The Israeli plan may be unilateral in nature, but Mr. Makovsky notes that even unilateralism requires negotiations. Accordingly, Mr. Olmert will seek American diplomatic and financial support for withdrawal during his forthcoming Washington visit. That support appears inevitable, for the American government never opposes Israeli withdrawal from territory.

But before the president and congress rubber-stamp Mr. Olmert’s initiative, they might consider some of its negative implications for American security as spelled out in an important report by Caroline Glick for the Center for Security Policy. In “Ehud Olmert’s ‘Convergence’ Plan for the West Bank and U.S. Middle East Policy,” Ms. Glick cautions that Mr. Olmert’s plan likely will harm American security interests by destabilizing Israel and Jordan.

In painstaking detail, she documents how the 2005 Israeli retreat from Gaza radicalized Palestinian Arab society, caused Gaza to descend into anarchy, opened it to global terror forces, jeopardized Israel’s national infrastructure, tied down Israeli troops, permitted the build-up of a substantial Palestinian arsenal, and created a range of new Israeli problems with Egypt.

She predicts that, in similar fashion, handing territory to the Palestinian Authority will destabilize the West Bank, harm Israel, and “directly threaten the survivability of the Hashemites” in Jordan. This damage will have many negative implications for America, she argues, by:

* Endangering American military assets warehoused in Israel and Jordan.

* Enhancing the prestige of states that sponsor Palestinian Arab terrorists.

* Strengthening the Hamas-run Palestinian Authority which, with its Syrian, Iranian, and Hezbollah allies, will provide what Ms. Glick calls “a training, logistics, and information warfare base” for terrorist groups at war with America.

* Threatening the land routes through Israel and Jordan that supply American forces in Iraq.

* Enabling terrorists fighting American forces in Iraq to establish training bases in the West Bank.

* Creating a perception of American weakness, given that Israel is so widely seen as an agent of Washington.

* Gratuitously handing a victory to Islamists and jihadists.

The American government has since the 1950s invariably encouraged Israeli governments to withdraw from territory, and I expect that pattern to continue. But it bears notice that several members of Congress – including Senators Schumer and Helms – have voiced their concerns when they see Jerusalem endangering its security by giving up too much land. Could such caution not conceivably take hold within the executive branch too?

Against all hope in December 2000, I appealed to the Clinton administration to buck up its faltering ally by adopting several measures, in particular the discouragement of further Israeli territorial concessions. Today, I appeal to the Bush administration to recognize how wretchedly the Gaza withdrawal is turning out, to look beyond the easy attractions of another Israeli retreat, and to be aware of the dangers of a unilateral retreat by Israel on the West Bank for it, for Jordan, and for America.

Mr. Pipes (www.DanielPipes.org) is director of the Middle East Forum and author of Miniatures (Transaction Publishers).