Israel returned to politics Thursday as Prime Minister Ariel Sharon remained comatose a week after a massive stroke, with his allies jockeying for position and his main rival ordering his party's ministers to quit the Cabinet.

The central committee of Sharon's forsaken Likud party was expected to choose a list of candidates Thursday for March 28 national elections, with polls showing the party losing more than half its strength from the last vote — when Sharon was the leader. The same polls show the prime minister's new party, Kadima, maintaining a huge lead despite — or perhaps helped by — his illness.

Sharon's successor as Likud leader, ex-premier Benjamin Netanyahu, ordered his party's Cabinet ministers to quit. But Israeli media reported that the four ministers would ignore the order, plunging the hard-line movement, already reeling from Sharon's defection, into further disarray. Netanyahu had planned to withdraw the party from the government, but suspended the order following Sharon's massive stroke Jan. 4.

Uncertainty over Sharon's condition has clouded Kadima's campaign plans.

Sharon's condition was unchanged Thursday — critical but stable, according to Hadassah Hospital in Jerusalem, where he was being treated. A statement said his heart rhythm was regular and he would undergo a routine CT scan later in the day.

Sharon's doctors said Wednesday they hoped to completely remove him soon from the sedatives that have kept him in a coma since the stroke — a process that could take a day and a half. Doctors said after the sedatives were stopped that it would be days, perhaps weeks, before a full picture of the damage from the stroke emerges.

"We're talking about a long, slow and drawn-out process and we hope that it will always develop positively. It's very hard to say what the pace will be," Dr. Yoram Weiss said.

One of Sharon's neurosurgeons, Jose Cohen, said most patients open their eyes within three weeks after sedation, and the sooner this happens, the better. However, Sharon was certain to have sustained some cognitive damage, he said.

"There will be changes, but what changes, nobody knows," Cohen told Israel TV.

Sharon's closest ally, Ehud Olmert, has taken over as acting prime minister. If Sharon is ruled permanently incapacitated, the Cabinet would have to pick a replacement until the election — probably Olmert.

Since Sharon's stroke, Olmert has worked to project an air of stability, holding Cabinet meetings and assuring the country that the government was functioning normally. He spoke with Russian Foreign Minister Sergey Lavrov on Wednesday and gave him an update on Sharon's condition.

Olmert had previously been seen as an unlikely candidate for prime minister, but his calm stewardship of the crisis has turned him into the clear front-runner.

A poll for Channel 10 TV and the Haaretz daily projected that an Olmert-headed Kadima would win 44 of 120 seats, an outcome that would virtually assure it would lead the next government. Likud and the dovish Labor Party trailed with about 15 seats each. Pollsters questioned 640 voters but did not give a margin of error.

Kadima politicians cautioned against reading too much into the poll, while experts said the results might reflect sympathy for Sharon's plight and might not hold.

"We know about the limitations of these polls," Kadima lawmaker Haim Ramon told Israel TV. "This just says that it depends on what we do. This week we acted well."

Sharon formed the party late last year, bolting from Likud after many of its lawmakers tried to torpedo his plan to withdraw from the Gaza Strip.

Though many experienced politicians joined the centrist Kadima, it was largely seen as a one-man show. Sharon had not yet drawn up the party's election list — a difficult and often divisive process — when he suffered his stroke.

On Wednesday, some Kadima officials discussed running Sharon symbolically in the top position on the list, but making Olmert their candidate for prime minister. "Let's say that (Sharon) has serious physical limitations, but in all other capacities he functions. There is no one better than him for the first place," Ramon said.

Tourism Minister Abraham Hirchson, also of Kadima, said the party should wait to see Sharon's condition before making a decision.

Opposition politicians, however, criticized the idea.

"I don't think that at the moment Sharon should be seen as some kind of electoral asset to be used by Kadima or anyone else," Likud lawmaker Yuval Steinitz told Israel TV, dismissing the proposal as "inappropriate."

Other politicians appeared to accept that Olmert would take Sharon's place as leader of the party. "I'm waiting for Ehud Olmert to come out and say what exactly the Sharon tradition means to him," Labor lawmaker Yuli Tamir said. "Then we can have a proper political debate."