With its capture of at least a third of the vote in Wednesday's parliamentary election -- and the possibility of an outright victory -- the Islamist group Hamas has cemented its place in the heart of the Palestinian political establishment and fundamentally altered it.
But the group now faces dilemmas it has never confronted before. Win or lose, Hamas will have to decide whether to enter into a parliamentary alliance with its archrival, Fatah. Should it fail to win a majority, it must decide whether to take Cabinet positions in a new government controlled by Fatah.
Most important, it must decide whether to formally renounce its stated goal of Israel's destruction and open the way for talks with the Jewish state.
With roots in the rubble-strewn streets and teeming mosques of Gaza Strip refugee camps, Hamas has always harbored deep mistrust of the secular-minded ruling Fatah movement. The group's very name, an Arabic acronym for Islamic Resistance Movement, was a deliberate rebuke to all who sought accommodation of any kind with Israel.
At times during the last decade, Hamas' enmity toward Fatah has rivaled its hatred of Israel. Many rank-and-file Hamas activists, along with senior leaders, have served time not only in Israeli jails, but in Palestinian Authority prisons.
Hamas by no means speaks with one voice on crucial questions involving its stance toward Israel, even when the same person is doing the talking. In recent days, views aired by Hamas candidates and officials have ranged from conciliatory to studiedly vague to utterly unyielding.
"Never!" snapped Mahmoud Zahar, a senior figure in the group, when asked Wednesday whether Hamas would recognize Israel. But Zahar, one of the few members of Hamas' upper echelon to escape assassination by Israeli forces over the last 2 1/2 years, also said this week that negotiations with Israel were not "taboo," especially if conducted through a third party.
Those who have closely observed Hamas through the years note its tendency to scrap any strategy the group believes has run its course, without necessarily trumpeting the fact that it is doing so.
Hamas did not carry out any suicide bombings inside Israel in 2005, a period that coincided with its first entry into the political arena. That strategic shift paid off with victories in municipal elections that gave Hamas control of dozens of cities, towns and villages across the West Bank and Gaza.
Over the last two decades, Hamas built a formidable following by trading on its perceived standing as an outsider, even an underdog. Being part of the Palestinian power structure will inevitably change that dynamic.
"It's good that the people are with us," Imad Afana, a Hamas election observer, said as he watched his refugee-camp neighbors waiting patiently to cast ballots Wednesday. "But we cannot pretend that the result will not be complicated for us -- very, very complicated."
Governance of the West Bank and Gaza Strip, as the Palestinian Authority has long since discovered, is messy. Hamas honed a reputation for fiscal integrity while administering its far-flung network of schools, clinics and charities, but playing any significant role in the sprawling, ineffectual Palestinian bureaucracy carries the risk of taint.
"You are about to enter the Authority; we warmly greet you," senior Fatah candidate Mohammed Dahlan rather sardonically told Zahar during a televised debate this week. Then came the zinger: "It's time for you to become acquainted with the suffering of being in government."
The Palestinian election campaign bared fault lines within not only Hamas, but Israel. Impassioned debate has broken out over whether the Jewish state can possibly have any political dealings with a group whose suicide bombings wrought carnage on commuter buses and in crowded cafes and markets.
"It is important to understand that the participation of terror elements in democratic elections ... is a Trojan horse that will destroy democracy from within," Ron Prosor, director-general of Israel's Foreign Ministry, told an academic conference this week.
But former Prime Minister Shimon Peres, a senior figure in the centrist Kadima Party that is expected to win Israel's March 28 general election, argued that Israel should realize that pragmatic self-interest may have changed Hamas' agenda.
"We are not fighting against a name -- we are fighting against a situation," Peres told Israel Radio this week. "If the situation changes, then what difference does a name make?"
Already, Israel is starting to draw a distinction between dealing with a Palestinian government in which Hamas takes part and one controlled by Hamas.
The Bush administration, too, appeared to be giving itself room to maneuver. Though the United States considers Hamas a terrorist organization and refuses any direct dealings with it, State Department spokesman Sean McCormack on Tuesday refused to rule out negotiations with a Palestinian government that included Hamas ministers.
Some observers point out that a Hamas role in government would give Israel the advantage of dealing with a ruling body that better represents the spectrum of Palestinian political views, perhaps making for more realistic talks.
"This time around, everything that was hidden during years of negotiations will finally be on the table," Nasser Laham, editor in chief of the Palestinian news agency Maan, wrote in a commentary for the Israeli newspaper Maariv.
A premier Israeli political commentator, Nahum Barnea, warned that with Hamas as a player in government, the fractious Fatah would have to pull itself together or risk being outflanked.
"In the new Palestinian parliament, a cohesive and disciplined Hamas faction will contend with a disintegrated and conflicted Fatah," Barnea wrote in the Yediot Aharonot daily.
In historical terms, any Israeli decision to engage Hamas would be reminiscent of its policy shift toward the Palestine Liberation Organization after it recognized Israel's existence, opening the path to negotiations.
"The entire process calls to mind what happened to the PLO," said Shaul Mishal, a Tel Aviv University professor whose specialty is Hamas. "I understand that this is a long, rough road, but these are the new Palestinian politics, and this could be the light at the end of the tunnel."
Although Fatah cannot help but be stung by Hamas' latest showing of electoral strength, its senior officials may sense a fresh opportunity to co-opt the Islamist group rather than try to defeat it in a head-on military confrontation. That has been Palestinian Authority President Mahmoud Abbas' wish all along.
"What we see is that Hamas may change its views," Abbas told the satellite TV channel Al Arabiya this week.
Hamas is reluctant to tip its hand about disarming, and for now, the group plainly intends to have it both ways.
"The Europeans and Americans are telling Hamas to choose between having weapons and being in government," said Ismail Haniya, the top Hamas candidate. "But we say we will go for arms -- and parliament."