ISRAEL HAS completed its evacuation of Jewish settlers from the Gaza Strip and northern West Bank far more quickly and easily than virtually anyone -- including the government of Ariel Sharon -- expected. There were wrenching moments as Israeli soldiers forced families from their homes, and tense ones as they dislodged militant protesters who congregated in synagogues. But no lives were lost, and the removal was completed in one-third the time expected. For that outcome, Israelis and Palestinians can thank the professionalism of the Israeli army; the Palestinian Authority should also be credited for helping to prevent what could have been ruinous attacks by militants. Above all the withdrawal is a tribute to Israeli democracy: proof that the majority can adopt and implement painful decisions and not be stopped by extremists.

The Gaza example will be vital as Israelis consider the future of their state, which sooner or later will have to contemplate a similar pullback from the West Bank. Jewish settlers there -- particularly those who live beyond the border-like system of fences and walls Israel is constructing -- are subject to the same logic that Mr. Sharon courageously articulated about Gaza: Their dream of holding the land forever is unattainable. As in Gaza, a withdrawal from the West Bank eventually will have to occur whether or not Israel receives any concessions from the Palestinians in return. But Palestinians, too, should have learned something: Israel is capable of making the pragmatic and painful sacrifices necessary for a lasting peace settlement. Palestinians have yet to convincingly demonstrate -- in deeds, as opposed to words -- that they can do the same.

That's why the first response to the question of what comes after Gaza must be: Gaza. The Palestinian Authority must prove that it is capable of setting up and leading a civilized democratic state. That means disarming Islamic extremist movements even while giving those groups the opportunity to compete peacefully in elections; channeling development aid quickly into labor-intensive development projects; and using force without hesitation against any attempt to use Gaza as a base for attacks against Israel. As President Bush suggested this week, without progress in these areas it will be impossible to move toward a final settlement.

That shouldn't mean Mr. Sharon has no further obligations. The success of Palestinian moderates depends heavily on their ability to deliver improvements on the ground that require Israel's collaboration. Though the settlers are gone, Palestinians in Gaza still have no freedom to travel from the strip or to export products efficiently; agreements with Israel on these points are long overdue. Mr. Sharon pledged months ago to withdraw Israeli forces from Palestinian West Bank towns and remove roadblocks that make daily life there miserable. He also promised the Bush administration that dozens of West Bank settlement outposts his own government defines as illegal would be dismantled. The Gaza operation shows that if he is serious about these commitments, he can deliver on them.