For Egyptian President Mohammed Morsi and his Muslim Brotherhood backers, it's hoped that the move will quell protests across the country against Morsi's decision to grant himself near-autocratic authority.
The 100-member panel tasked with writing the constitution rushed to complete the final draft on Wednesday before putting it to a vote in the national assembly. If it passes, the document would have to be approved in a public referendum.
The Islamist-dominated assembly vote began Thursday at 2:40 p.m. in Cairo (7:40 a.m. ET), and was attended by only 85 legislators, many of whom wore long beards — a mark of conservative Islam. No Christians were present and the four women were also Islamists.
Several Christian and Liberal council members had walked out of parliament in protest of Morsi's decrees last week granting himself new, far-reaching powers.
CBC's Susan Ormiston, reporting from Cairo, said the vote would last several hours as the members continue to pore over details in the document's more than 230 articles.
While they were doing that, Morsi defended his power grab and the new draft constitution Thursday evening in his first broadcast interview since he decreed the sweeping powers last week.
Meanwhile, thousands of people filled Cairo's Tahrir Square for another night of protesting against the president's actions.
An official from the Muslim Brotherhood told the Reuters news agency that the party hopes the countrywide protests will end after the constitution replaces Morsi's controversial decrees.
But others believe the new constitution will only inflame tensions between pro- and anti-Morsi camps, Ormiston reported.
The decrees announced by Morsi last week included immunity for the constitutional assembly from any possible court decisions to dissolve it — a threat that had been hanging over the controversial body.
Morsi had also given the assembly two more months to try to iron out the sharp differences over the draft, but when Egypt's Constitutional Court defied his decree and said Wednesday that it would rule on the panel's legitimacy, the date of the vote was immediately moved up.
Morsi is expected to call for a referendum on the draft as early as mid-December.
Several demonstrations have been planned in Cairo in the coming days, Ormiston said. Anti-Morsi protesters will gather Friday, while his supporters are set to rally on Saturday.
Last Tuesday, more than 200,000 protesters packed Tahrir Square in the biggest challenge yet to the president. Morsi's opponents demanded that he rescind the decrees, which they say give him near-dictatorial powers.
Critics have also accused the president and the assembly of trying to push through an Islamic vision of Egypt that would lead to restrictions on the rights of women and minorities.
Morsi and his supporters say his decrees were necessary to "protect the revolution" and prevent the judiciary from holding up what they say is a transition to democracy.