JERUSALEM — Hamas’ sweeping election victory is forcing all key players to reassess their positions on the Israeli-Palestinian conflict and has created a widespread sense of uncertainty about the future, with Israelis, Palestinians and outside observers raising a host of fundamental questions.

The big question is whether Hamas in power will moderate its radical positions or put Palestinian society on a collision course with Israel and the western world.

There will be enormous pressure on Hamas to adopt a more pragmatic line. The European Union, which provides up to 90 percent of international aid to the Palestinians, is threatening to suspend its economic support unless Hamas recognizes Israel’s right to exist and renounces violence.

In the short term, cutting off these funds could leave a Hamas government unable to pay the salaries of 155,000 Palestinian civil servants, including the 30,000-strong Palestinian Authority security forces. In the longer term, ambitious plans to jump-start the stalled Palestinian economy may have to be shelved, perpetuating poverty and unemployment.

A militant Hamas also will face international isolation, giving Israel the moral and diplomatic high ground for tough responses to Palestinian terror.

Israel will be able to exert tremendous diplomatic, economic and military pressure. On the diplomatic front, it won’t talk to Hamas in its present form; as to the economy, the Palestinians are dependent on Israel for electricity, the transfer of tax revenue, goods, services, work places and border crossings; and, if terrorism escalates, Hamas leaders could become targets.

Therefore, while it won an outright majority of 76 of the 132 seats in the Palestinian Legislative Council, Hamas wants the defeated Fatah movement to stay on in government to give it a semblance of respectability vis-a-vis Israel and the international community.

Still, despite all the international, Israeli and domestic pressure, Hamas for now probably will refuse to moderate its ideology, which calls for Israel’s destruction. Indeed, there are strong opposing pressures on Hamas to maintain its radical line.

Iran, for example, could make up for funds the E.U. withholds — on condition that Hamas remain militant. Fidelity to its ideology, and goading by other militant groups, also could shunt Hamas away from moderation.

* Does the Hamas victory mean the end of the dynamic toward independent Israeli and Palestinian states living side-by-side?

Not necessarily. By its very participation in the election Hamas has been sucked into the two-state paradigm: The Palestinian Parliament holds sway in the West Bank and Gaza Strip but not over all the territory — including Israel — that Hamas claims as “Palestine.”

More importantly, the Hamas victory likely will accelerate unilateral Israeli moves to establish a clear border between Israelis and Israeli settlements on one side, and Palestinians on the other.

* Is Hamas uniformly radical, or are there more moderate voices?

The organization’s formal position is that there can be no talks with Israel until it withdraws to its pre-1967 boundaries, divides Jerusalem and takes in vast numbers of Palestinian refugees, positions that are unacceptable to Israel. Until then, Hamas says, all contacts will be through third parties.

Behind the scenes, however, some Hamas leaders are intimating that there could be direct negotiations before then. On this score, and in general, Ismail Haniya, Hamas’ primary candidate for prime minister, is thought to be more pragmatic than the Gaza-based party leader, Mahmoud Zahar.

* How is the secular Fatah movement likely to respond to its loss of power?

Fatah, the movement founded by Yasser Arafat, has dominated the Palestinian nationalist movement since its inception 40 years ago. Its loss of power to the Islamic fundamentalists came as a profound shock.

Fatah leaders’ initial reaction was to dismiss out-of-hand Hamas calls to participate in a national unity government on the grounds that Fatah plans to rebuild in opposition and return to power once Hamas’ approach proves unrealistic.

Fatah says it intends to hand over power peacefully, but already there has been some fighting between the two groups and some talk of using force to reverse the election result, the way the army did when Islamists were poised to win power in Algeria in 1992. A key development to watch will be whether P.A. security personnel loyal to Fatah agree to place themselves under Hamas command.

* What are the likely regional consequences?

For Israel, one of the most dangerous results would be a growth of Iranian influence in the Palestinian arena. Hawks like the Likud Party’s Yuval Steinitz, chairman of the Knesset’s Foreign Affairs and Defense Committee, see a tightening of an Iranian-controlled terrorist belt around Israel, with the Lebanese-based Hezbollah to the north and Hamas and other Palestinian militants in the center and south.

A lot will depend on the choice Hamas makes between Iran and the rest of the international community.

* Will Hamas continue the ceasefire, or ‘tadiya,’ that most Palestinian terrorist groups declared in early 2005, or will there soon be a fresh outbreak of terrorism?

The Israeli intelligence assessment is that Hamas will observe the ceasefire, at least in the short term. What happens next will depend on the long-term strategy that Hamas, with all the constraints of power, decides to adopt.

As for terrorist acts by other militants, such as Islamic Jihad, Hamas, with its radical ideology, will be in no position to condemn them.

Some Israelis are saying this will make it easier for Israel to cope. There will be no more masks or double talk, analysts say, such as when the Palestinian Authority condemned terror to the outside world but did nothing to stop it. With Hamas in power, they add, Israelis are likely to be more united in fighting terrorism and to get more international support for counter-terrorist activities.

* What are Israel’s options?

Government policy is shaping up as the following: No talks with Hamas, persistence with the “road map” peace plan’s demands for a renunciation of terrorism and disarming of militias, consideration of further unilateral withdrawals, rapid completion of the West Bank security fence, targeting of the Islamic Jihad militia and carrot-and-stick use of Israel’s economic leverage.

On the left, Meretz Party leader Yossi Beilin suggests circumventing Hamas by negotiating peace with Fatah leader Mahmoud Abbas, who will remain as P.A. president, and putting any deal to a Palestinian referendum.

On the right, Likud leader Benjamin Netanyahu urges moving the fence deeper into Palestinian territory.

* What impact is the rise of Hamas likely to have on Israeli elections?

Likud argues that last summer’s unilateral withdrawal from Gaza and the northern West Bank showed the Palestinians that terrorism pays, and the fact that Hamas could claim that its militiamen forced Israel to leave paved the way for its election success.

On the left, Labor and Meretz claim that the Sharon government weakened Abbas and Fatah by ignoring them as potential peace partners, which they say contributed to Hamas’s rise.