The body drafting Egypt's new constitution will start voting on a final draft on Thursday, a move President Mohamed Mursi's allies in the Muslim Brotherhood hope will help end a crisis prompted by a decree expanding his powers.
Mursi is expected to call for national unity in a public address at 7.00 p.m. (1700 GMT), seeking to ease the crisis, which has set off a week of protests and threatens to derail early signs of economic recovery.
Two people have been killed and hundreds injured in countrywide protests ignited by the decree Mursi issued last Thursday, which gave him sweeping powers and placed them beyond legal challenge, deepening the divide between the newly empowered Islamists and their opponents.
Setting the stage for more confrontation, the Muslim Brotherhood and its Islamist allies have called for pro-Mursi protests on Saturday in Tahrir Square, where a sit-in by the president's opponents entered a seventh day on Thursday.
The Muslim Brotherhood, the Islamist group that backed Mursi for president in June elections, hopes to end the crisis by replacing the controversial decree with an entirely new constitution to be approved by popular referendum.
It is a gamble based on the Islamists' belief that they can mobilise enough voters to win the referendum. They have won all elections held since Hosni Mubarak was toppled from power last year.
But critics say the bid to finish the constitution quickly could make matters worse.
The constitution is one of the main reasons Mursi is at loggerheads with non-Islamist opponents. They are boycotting the 100-member constitutional assembly, saying the Islamists have hijacked it to impose their vision of Egypt's future.
The assembly's legitimacy has been called into question by a series of court cases demanding its dissolution. Its standing has also been hit by the withdrawal of members including church representatives and liberals.
The Brotherhood argues that approval of the constitution in a referendum would bury all arguments about both the legality of the assembly and the text it has written in the last six months.
Once the assembly approves the draft it will go to Mursi for ratification - a step expected at the weekend. He must then call the referendum within 15 days.
Once the constitution is approved in a referendum, legislative powers will pass straight from Mursi to the upper house of parliament, in line with an article in the new constitution, assembly members said.
"This is an exit. After the referendum, all previous constitutional decrees, including March 2011's decree and the current one that created all this political fuss, will fall automatically after 15 days," Muslim Brotherhood spokesman Mahmoud Ghozlan said.
Egypt has been without an elected legislature since the Islamist-dominated parliament was dissolved in June. New parliamentary elections cannot happen until the constitution is passed.
The constitution is supposed to be the cornerstone of a new, democratic Egypt following Mubarak's three decades of autocratic rule. Mursi had extended its Dec. 12 deadline by two months, but the assembly speaker said the extra time was not needed.
The constitution will determine the powers of the president and parliament and define the roles of the judiciary and a military establishment that had been at the heart of power for decades until Mubarak was toppled. It will also set out the role of Islamic law, or sharia.
"The secular forces and the church and the judges are not happy with the constitution, the journalists are not happy, so I think this will increase tensions in the country," said Mustapha Kamal Al-Sayyid, a professor of political science at Cairo University. "I don't know how the referendum can be organised if the judges are upset," he added.
Egyptian elections are overseen by the judiciary.
"It may be regarded with hostility by a lot of state actors, too, including the judiciary," he said.
Leading opposition figure and former Arab League chief Amr Moussa slammed the move. He walked out of the assembly earlier this month. "This is nonsensical and one of the steps that shouldn't be taken, given the background of anger and resentment to the current constitutional assembly," he said.
The decree issued by Mursi last Thursday has set him further at odds with opponents and worsened already tetchy relations with the judges, many of whom saw it as a threat to their independence. Two of Egypt's courts declared a strike on Wednesday.
Mursi was unrepentant in a Time magazine interview published overnight.
"I think you have seen the most recent opinion surveys. I think more than 80, around 90% of the people in Egypt are - according to these opinion measures - they are with what I have done. It's not against the people, It's with the people, coincides with the benefits," he said.
Among other steps, the decree shielded from judicial review all decisions taken by Mursi until the election of a new parliament.
His opponents say it exposed the autocratic impulses of a man who was once jailed by Mubarak. Western governments expressed concern, and Human Rights Watch said it had given the leader more power than the military establishment he replaced.
In his speech, Mursi was expected to explain why he had issued the decree and to outline what he saw as conspiracies being planned by his opponents, officials said.
A constitution must be in place before a new parliament can be elected.