Lt. Gen. Ehud Barak, then Israel's top army officer, was taken by surprise when he learned of the Oslo peace deal between Israel and the Palestinians six years ago, and he expressed grave reservations.

Two years later, as a freshman government minister, Barak was equally skeptical when a follow-up accord required Israel to go ahead with pledged troop withdrawals from large chunks of the West Bank. In the cabinet vote on the agreement, he abstained.

Now, as prime minister for just a month, Barak is again eyeball to eyeball with what he regards as the core problem in Middle East peacemaking: the expectation that Israel will make good on its promise to hand over more occupied territory to the Palestinians--and face domestic opposition as a result--before getting down to business on a comprehensive peace agreement.

Much as Barak balked at the sequence of Israeli withdrawals set forth in the original Oslo accord, he is hesitating now to carry out the land transfers mandated by last October's Wye River agreement, the latest attempt to give the Oslo process a shove forward. Instead, he wants to link further Israeli pullbacks to the big prize in Middle East peacemaking--a broad deal outlining final arrangements between the two sides.

His hesitation has produced the first impasse in what had begun to look like a new era of reconciliation between Israelis and Palestinians. Invective and suspicion have suddenly changed the atmosphere from the days just after Barak's inauguration last month, when he and Palestinian leader Yasser Arafat embraced and called each other "partner" and "friend."

The snag is also presenting the Clinton administration with the problem of how to get things moving without defying Barak's explicit request that the United States stop playing referee between the negotiating parties. Thus far, the United States has merely reiterated its policy that the Wye accord should be carried out in full by both sides.

In part, the shift in tone reflects the legacy of three years of relative inertia during the tenure of Barak's predecessor, Binyamin Netanyahu. To restore Palestinians' faith in the peace process, analysts say, Arafat needs urgently to show results--which is to say, land. And he is in no mood to trust Barak's assurances of a big payoff if he waits.

The two sides remain far apart on the big issues they were meant to start resolving three years ago but never really did: the future political status of Jerusalem, the fate of Palestinian refugees and Jewish settlers, the location of final borders, the disposition of water resources.

But Israelis and Palestinians are also divided by strategic differences over the meaning of the land-for-peace formula--and indeed over which comes first, land or peace. "It's a more fundamental disagreement than just the logistics of implementation," said Ghassan Khatib, director of the Jerusalem Media and Communications Center, a Palestinian research organization. "We have a difference in conception in this whole interim agreement between the two sides."

Said David Makovsky, editor of the English-language Jerusalem Post: "Barak's point of departure is a distaste for incremental peacemaking. It should not be interpreted as being opposed to land-for-peace, but rather a belief that incrementalism is a kind of twilight zone in the peace process that doesn't really give Israel security."

The blueprint laid out in Oslo in 1993 called for a five-year countdown to a comprehensive peace, during which each side would take steps to build trust and confidence in the other. The Palestinians would establish a government and crack down on anti-Israeli extremists; the Israelis would hand over chunks of territory in the Gaza Strip and the West Bank.

As trust was established and the process moved forward, the sides would begin talks to determine arrangements for a durable peace. Although Palestinian statehood was not mentioned, most Palestinians and many Israelis came to see it as implicit.

These "final status" negotiations were supposed to start in May 1996 and be completed by May 4, 1999, but they never really began. The linkage between land transfers, trust-building and final status talks was lost.

As chief of the army, Barak saw the interim period of piecemeal land transfers and confidence-building as a recipe for security risks for Israelis. As Palestinian-controlled territory expanded bit by bit, it would be more difficult to protect the increasingly isolated Jewish settlements in the West Bank, where about 170,000 people have taken up residence with encouragement and aid from the Israeli government.

As prime minister, his view is that with each successive pullback, Israel would give away bargaining chips best reserved until the end game and risk a backlash from Jewish settler groups that are part of his coalition government. This, he fears, would leave him politically weaker even before entering final status talks.

In keeping with that view, Barak wants not only to postpone the last and largest of the three Israeli pullbacks promised in the Wye agreement--withdrawing from another 7 percent of the West Bank--but also to tie it to a broad agreement on the shape of the final peace deal. He has suggested a negotiating timetable of six months, with the goal of reaching a blueprint for a comprehensive agreement and carrying out the 7 percent withdrawal by next Feb. 1.

In return, his aides have hinted Israel would sweeten the Wye deal, perhaps by handing over more, or more desirable, parcels of land than agreed to.

But, having wrestled with Netanyahu to little avail for the last three years, Arafat wants all the land promised by Israel under the Wye agreement--13 percent of the West Bank, which would put a total of 40 percent of that territory under full or partial Palestinian control. That is far less than the Palestinians expected to have by this point and still too little to build the state they urgently want.

"We don't have much trust that we'll reach a final agreement," said Khatib, the Palestinian analyst. "That's why, for the Palestinians, Wye is a bird in hand, better than two in the bush."