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With medical experts saying Prime Minister Ariel Sharon has little chance of returning to politics following his devastating stroke this week, many are questioning the future of not only internal Israeli politics but of the entire Middle East peace process.

Some observers are wondering if there is another robust, commanding leader within the newly formed Kadima (Forward) party who can effectively steer the organization and who can ensure that progress continues in reconciling differences between Palestinians and Israelis after years of bloodshed.

Many Israelis felt Sharon was best positioned to draw Israel's final borders in a settlement with the Palestinians. In September, he orchestrated Israel's exit from the Gaza Strip, becoming the first Israeli leader to turn over land to the Palestinians for their future state.

"Mr. Sharon has been the prime minister for almost five years, he's well known as a war hero, as a very assertive fighter against terror, but he did this very significant move towards peace, with the disengagement from Gaza last summer," Ambassador Arye Mekel, Israeli consul general, told FOX News.

"Certainly his presence is very critical, very important. But if he cannot continue as prime minister, I think we will not see major changes in the policy," Mekel said. "We have an election, after the election, we'll see who wins the election, and then we'll move on. But right now, until the end of March, we will not see any major changes."

The national election will be held March 28.

Sharon had been expected to face off against former Prime Minister Benjamin Netanyahu, who recently won the primaries for the Likud Party, which Sharon left when he formed Kadima. Sharon also was expected to compete against Amir Peretz, the union leader who recently unseated veteran Israeli politician Shimon Peres as head of the liberal Labor Party.

"It's unclear now who is going to lead that party ... it appears to be unstable," said Ambassador Alon Pinkas, former Israeli consul general, noting that the Kadima party is an interesting collection of right- and left-wing politicians, as well as centrists.

"The whole thing is a one man-show ... will there be someone to succeed him?" Pinkas asked. "There are good people in that party who are well experienced and capable to do that, but that party doesn't even have a mechanism which they can select or appoint that person, which is why it's chaotic right now."

Sharon was rushed back to surgery Friday after a brain scan revealed an increase rise in pressure on his brain and more internal bleeding. That operation followed a seven-hour procedure Thursday morning after the Israeli leader suffered a massive brain hemorrhage. Doctors had put him in a medically induced coma to give his body time to heal, but many experts believe his chances for recovery are slim, since he likely suffered irreversible brain damage.

Sharon's deputy, former Jerusalem mayor Ehud Olmert, took power after Sharon became disabled Wednesday night and could emerge as Sharon's successor as head of the Kadima party. But none of Sharon's possible successors was seen as having his ability to pull together the next ruling coalition.

Former Senate Majority Leader George Mitchell, a Democrat who also used to serve as a U.S. peace envoy to the Middle East, said Olmert is an able and experienced leader but he is expected to have a far tougher time beating either Netanyahu or Peretz than Sharon would have in the elections.

"He will no doubt pursue the policies that Sharon has established but the question is — will he get elected? You tend to gain charisma after you get elected, not before," Mitchell said.

"This probably strengthens the hand of Benjamin Netanyahu in making a comeback," added former U.S. House Speaker Newt Gingrich, R-Ga. "The Israeli people will find a leader and will find a strategy for survival. But it does mean, I think, that finding a strategy for defeating the terrorists becomes more difficult in the next six to eight months."

Aaron Miller, former deputy Middle East coordinator and former adviser to six secretaries of state, said no one can predict either the outcome of the March elections or the survival of Kadima.

"The question is whether the prime minister's party that he has recently established with the toughness that I suspect that most Israelis want out of a party and leader, whether that party will survive the prime minister's passing ... sadly, if he should be removed from the scene," Miller said.

Miller called this "the most consequential development in Israeli politics" since the assassination 10 years ago of former Prime Minister Yitzhak Rabin.

"Like Rabin's murder, this development will be negative for Israel, for American interests and for the prospects of Israeli-Palestinian peace," he added.

Rabin, the first Israeli-born prime minister, played a leading role in the signing of the Oslo Accords, which created the Palestinian Authority and gave it partial control over portions of the West Bank and Gaza Strip. He was awarded the 1994 Nobel Peace Prize for his Oslo efforts. During his second term in office, Rabin oversaw the signing of the Israel-Jordan Treaty of Peace in 1994.

Miller said Sharon helped create new possibilities for peace by developing the "unilateral withdrawal" approach.

"It wasn't perfect, but the fact is that it has improved or has the potential to improve Israel and the Palestinian situation. And I suspect that had he not had this medical issue, Prime Minister Sharon would have gone on to consider further withdrawals from the West Bank," Miller said.

There's a high level of uncertainty and instability among both Israelis and Palestinians as to what happens next, Mitchell said.

"I think it [peace process] can move forward but not until elections are held on both sides so we have some indication on what leadership we're dealing with," Mitchell added.

Rob Sobhani, a Middle East politics professor at Georgetown University, said the Palestinians had a "reliable partner" in Sharon in that in recent years, he's turned from a hard-liner into a more middle-of-the-road leader intent on reducing the violence in the region.

Sobhani noted that there are several groups of Palestinians: the new generation who wants an end to corruption and increase transparency in government, the old timers like Palestinian leader Mahmoud Abbas and the radical fringe who seek the destruction of Israel.

"Unfortunately, with Ariel Sharon not there, there's a vacuum on the Israeli and the Palestinian side," Sobhani said.

Sharon had indicated that he expected significant progress toward peacemaking in 2006, despite continued violence and growing chaos in the Palestinian territories. Nonetheless, no major peace moves had been expected until after the Israeli elections in March and Palestinian parliamentary elections scheduled for Jan. 25. Palestinians, however, were already split on whether to proceed with elections.

"I wouldn't go so far as to say it's going to up in smoke but I would definitely say there's going to be a void in the political map," Pinkas said of the peace process.

One former top diplomat, Alexander Haig, said Thursday he wasn't so sure that the peace process will be derailed without Sharon.

"It's going to take an extra effort on the part of the United States that can't just afford to be unconcerned about the situation," said Haig, who served as secretary of state under President Reagan.

Sharon has had the strong support of President Bush, who supported Israel's withdrawal from Gaza. Bush had hoped Sharon could help fulfill the vision of a Palestinian state living side-by-side in peace with Israel, whereas Sharon was relying on Bush to compel the Palestinian leadership to quash terror groups.

White House spokesman Scott McClellan said the focus should remain on Sharon's health. He would not comment on how Sharon's condition might affect the Middle East peace process or about the transition of Israeli power.

"He lies immobilized in an Israeli hospital. We pray for his recovery," Bush said Thursday. "He is a good man, a strong man, a man who cared deeply about the security of the Israeli people and a man who had a vision for peace. May God bless him."

The Associated Press contributed to this report.