The Bush administration opposes timetables, and only reluctantly and begrudging accepts benchmarks, in regard to Iraq, but proposes both in regard to the Israel-Palestine conflict.

The idea animating the Acceleration Benchmarks for Agreement on Movement and Access for agreement on movement and access as well as on the Gaza security situation was to facilitate the flow of people and goods within and between the Palestinian areas in an attempt to allow the president of Palestine, Mahmoud Abbas, to claim concrete accomplishments. The AMA, developed by General Keith Dayton and pushed by Secretary of State Rice, died aborning, thanks to Palestinian factional fighting, their rocket attacks, and Israel’s self-defense.

Even before the latest deterioration, the Israelis were alarmed at the prospect of increasing and moving Hamas influence into the West Bank from Gaza. But taken together with the White House opposition to the congressional Democrats’ attempts to impose a date for withdrawal of American forces from Iraq, it highlights something important about American expectations. In both instances, the underlying point is that you can’t depend on the Arabs — certainly not on the Palestinians nor on the Iraqis. It is useless to make demands of them because they cannot be expected to accept them, or, if they do accept them, to live up to their commitments.

That’s why the Ms. Rice’s and Mr. Dayton’s AMA was full of timetables and deadlines for Israel, a partner that evokes a different set of expectations, and almost none for the Palestinians. It’s also why the President Bush and his team do not want to dictate timelines or establish benchmarks for Iraq’s government, since failure to meet them on time would trigger the beginning of the end of the American military deployment.

This assumption follows decades of agreement making and brokered deals, most of which shattered on the shoals of uneven performance by the Palestinians. One side (guess who) has been continually delinquent while the other could bob and weave, violating prohibitions by expanding settlements for example, but basically was expected to, and did, live up to its obligations.

Regarding the AMA, the collapse of this latest mini peace push by the administration amidst the current fighting also calls into question just how far the administration is willing to proceed based upon assurances from the Egyptians, Jordanians, and Saudis — none of whom appear able or willing to control Hamas beyond the constructively ambiguous language in the Mecca Agreement that led to the formation of the national unity government between Hamas and Fatah.

Why haven’t the Egyptians sealed off the Gaza/Sinai border to arms smuggling by Hamas, a process that according to Israeli military intelligence, has greatly enhanced the power at the disposal of the Islamic terrorists?

Why haven’t the Saudis used their enormous financial clout to rebuild Fatah and cripple Hamas?

A more politically correct way of stating this argument would be that Western power has reached a limit of sorts. The Arabs will bend so far and no farther. The continual shifting of the balance of power lays the foundation for a diplomatic settlement or long lasting stalemate.

The problem with the dual set of expectations in regard to Israel and the Arabs is that what is being asked of Israel is to forgo tangible assets such as the West Bank that, once relinquished, cannot be recovered. Under appropriate conditions, Israel would be wise to yield to a compromise. But these conditions do not currently apply, nor are they likely to in the near future. Here’s why.

Right now too many elements are in flux to see the outcome with any certainty. Israel’s faltering martial display last summer, as opposed to its impressive current pinpoint operations, and the ongoing political instability and weakness do not augur well.

Prime Minister Blair is leaving office and President Bush is forced to fend off a Congress captured by the impulse that anything is better than the status quo in Iraq.

Hamas and Hezbollah do not feel the need to kowtow as long as they believe their strategic hinterland, Iran, is a rising power. I am sure there are people in both movements who understand that the Islamic world lacks the power to destroy Israel — for now. But if Iran emerges in a stronger regional role — playing the role that Japan played in the late 1930s and inaugurating a Middle East version of the “Co-Prosperity Sphere” — they hope a future arrangement will be achieved on terms more favorable to the Muslims. For example, a West Bank-Gaza Palestinian state that does not arise from the recognition of and a peace treaty with Israel.

Unlike the Japanese, Iranian hegemony would be reinforced by a form of Islam, not race, although informed by Parsi nationalism and pride. Like the Japanese, the drive for regional leadership assumes the form of blatant anti-Westernism and makes common cause with all enemies of America and Great Britain, in Iran’s case.

Everything — both the fate of the Palestinian Arabs as well as that of the Iraqis — depends therefore not on how quickly the administration delivers the Israelis the deal envisioned by the quartet and backed by the international community, but on the outcome of the tensions between America and Iran.

Mr. Twersky is a contributing editor of The New York Sun.