CAIRO — The embattled Egyptian government on Tuesday named panels of jurists to reform the constitution of this one-party state, its latest effort to regain the initiative in shaping Egypt's future from the tens of thousand of chanting protesters in Cairo's main square.

Anti-government protesters, who appeared to come out in record numbers Tuesday, quickly rejected the committees and stuck to their refusal to negotiate until U.S.-backed President Hosni Mubarak steps down. Many of them called for suspending the constitution. If Mubarak didn't respect the rule of law, they reasoned, they shouldn't have to adhere to a constitution that was altered to keep him in power.

The tug of war underscores the central question before this nation of 80 million people, the touchstone for the Arab world: Will it evolve into a constitutional democracy through a prolonged reform process or does it first require a dramatic shake-up by ousting Mubarak as head of state?

Newly appointed Vice President Omar Suleiman announced in a televised address that committees of legal experts would hammer out amendments to Egypt's constitution, which now sets no presidential term limits, restricts political candidacy almost exclusively to the ruling party and leaves little room for judicial oversight in elections.

Political analysts, including those who are sympathetic to the popular rebellion, warn that drafting a constitution from scratch runs the risk of open-ended debates on minutiae when a more efficient approach might be for the opposition to work with the committees to strip away executive powers and then prepare a candidate for presidential elections this fall. That way, they said, if the protest movement loses steam, there's at least a greatly weakened presidency.

"The regime can wait them out — unless the crowds keep coming," said Tarek Masoud, an assistant professor at Harvard's Kennedy School of Government who closely monitors Egyptian politics.

The crowds came by the tens of thousands Tuesday, and for the first time many left Tahrir Square to set up a parallel camp in front of parliament. Emboldened by the high turnout two weeks into their uprising, protesters chanted against merely amending the constitution and, in slogans and on posters, deemed unacceptable any concession short of Mubarak's ouster.

Agreeing to work with the reform committees would involve a huge leap of faith by the opposition. The proposed amendments would have to be pushed through Mubarak's rubber-stamp parliament and then put to a national referendum overseen by his election officials. Mubarak would remain in office throughout the process, robbing the protesters of the symbolic victory of seeing him overthrown.

"At this point, the hard reality is that we may not get the cathartic moment of Mubarak's plane departing to the cheers of millions of Egyptians celebrating a new era," the Middle East scholar Marc Lynch wrote on his blog for Foreign Policy magazine. "The struggle is now shifting to the much messier terrain of negotiations over the terms of Egypt's transition."

The ruling National Democratic Party, whose leadership has changed in the past week as part of government concessions, says Mubarak is committed to the reforms and that parliament will follow his edicts to approve the constitutional amendments, which are expected in March.

"We need to focus on what guarantees we can formulate and what reforms we can put in place in coming weeks to build an electoral bridge to the summer," said a government aide who spoke only on the condition of anonymity because he isn't authorized to give public statements. "We're trying to translate, 'Your voice has been heard' into initiatives that are actually clear."

Such reassurances ring hollow to the opposition and its supporters, who say there's no reason to believe the ruling party would legislate itself out of power after a three-decade stranglehold on Egyptian political and economic life.

"They can't be trusted," said Mohamed Zakaria, 47, a civil engineer who was in Tahrir Square. "There's no millionth chance. They've had 30 years and did nothing."

Nevertheless, the committees began work Tuesday, with the wary approval of a handful of opposition factions. Parties involved in talks led by Suleiman say they expect little debate on setting term limits and bringing back judicial supervision of elections but that the real fight is going to be over Article 76, which now lays out extraordinarily narrow limits on candidacy.

Presidential hopefuls must gain the endorsement of 250 elected officials, including 65 members of the National Democratic Party-stacked parliament. As is, even well-known pro-democracy figures such as Nobel laureate Mohamed ElBaradei and Arab League chief Amr Moussa wouldn't be able to run.

ElBaradei has said in interviews that he favors abolishing the constitution, dissolving parliament and forming a caretaker government that would serve for a short time in order to set up elections. Other Egyptian intellectuals — legal scholars, human rights activists and political scientists — have proposed similar scenarios, but no cohesive plan has been put forward.

Mohamed Abdellah, the National Democratic Party's newly appointed assistant secretary general, acknowledged that Article 76 could be a sticking point. He asserted that Mubarak's immediate dismissal would lead to an extremist Islamist takeover or a military coup, statements designed to rattle the United States and Israel.

It's better for Egypt's stability, Abdellah said, to hash out the amendments and let voters decide their next president in September polls.

"There is a kind of consensus, at least in the mainstream of the opposition, that what's going to be achieved is a huge step," Abdellah said. "It's not going to happen overnight and, as with all negotiations, not all demands will be met."

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