Cairo, Egypt - At the heart of a stand-off that could see elections delayed and protesters pour back into Tahrir Square lies a single document: the constitution.
The religious undertones of the document are likely to set the scene for Egyptian politics and the wider region for decades to come.
"There's a lot of things that could shift," said Kirsten Stilt, a law professor at Northwestern University in the US who has studied the Egyptian constitutional debate. "What is written could play a big role in the future of the country, but it is also about who interprets it, how it is interpreted. These issues also come from who is in power."
If Islamist groups, such as the Muslim Brotherhood, achieve a large representation in the coming parliamentary elections, they could have a lasting impact on governance in Egypt and social life through the rewriting of the constitution.
Among the ideas that emanated from a body of work known as Islamic constitutionalism is the use of Sharia to dictate such diverse elements as how often divorced parents can see their children, the greater use of Islamic finance in the economy, and the creation of a religious body to advise the parliament on new laws.
These could affect how the state spends money, including reducing funding for art projects deemed to be immoral, analysts say.
Even if the constitution emerges as a liberal document with modest religious references, the make-up of the parliament could affect the appointment of judges that interpret the laws.
Debate over the 1971 constitution was relatively quiet under the 30-year regime of Hosni Mubarak, who pushed through several amendments in recent years to allow him even greater power. Now, as political parties form and presidential candidates begin to emerge, the fate of the constitution has become the largest issue facing Egypt's new democracy.
Some 36 groups, under a broad coalition called Constitution First, announced this week that they were seeking 15 million signatures to convince the caretaker government administered by the military to delay parliamentary elections scheduled for September and create a special body to write a new constitution. There have been calls for a million-man march on July 8 in Tahrir Square.
The Muslim Brotherhood and other groups have said those calls amount to an undemocratic strike against the people of Egypt. They are referring to a referendum in March, where 77 per cent of voters agreed to amend the constitution rather than rewrite it before elections.
Mohammed ElBaradei, a Nobel laureate and presidential candidate, has come forward with a possible solution to the stand-off. He proposes an Egyptian bill of rights that could be agreed upon by all the parties that would be added to the constitution when it is eventually created. The document, which includes basic freedoms such as the right to association but also includes religious language, was inspired in part by the German bill of rights, said Mohammed Naeem, a member of Mr ElBaradei's political campaign.
"We need something that will unify the parties on the issue of the constitution," he said. "Everything could be stalled without a way to move forward."
While the Muslim Brotherhood has not revealed much about its interest in the constitution, there could be serious ramifications in Egypt if they or other Islamist groups try to increase the use of language that relies on religious principles.
Some newly formed Salafist political groups, who adhere to a strict branch of Islam, have even advocated the implementation of a punishment regime known as hudud that includes harsher penalties such as stoning and "an eye for an eye", though this is not a widely advocated idea.
Islamic constitutionalism has a wide range of scholars and a growing body of work, but one unifying factor is a subtle but important change in the role of the state. Whereas democracies have traditionally used the constitution as a means to restrict the state, an Islamic constitution sees the state as a force for building a stronger Islamic society.
So far, the Muslim Brotherhood has been moving cautiously into politics, calling for similar rights as the liberal parties and avoiding a description of their grander visions for the future of Egypt. The way they talk about constitutional reform has become more muted in the aftermath of the revolution, said Bruce Rutherford, a professor of Middle East studies at Colgate University in the US.
"They have changed their terminology since the revolution to say they are seeking the objectives of Sharia law, rather than the implementation," he said. "The big issue is what this means. How far do they want to push this?"
A major force for a moderate interpretation of Islamic constitutionalism could be Mohammed Saleem El Awa, an Islamic law scholar who announced this week his candidacy for president. Mr El Awa is known as a cosmopolitan thinker who is concerned with preventing discrimination of different religions. He has articulated his vision of Egypt in dozens of books and articles over the past decades. He sees a state that derives its laws from Islam.
No matter how the debate and process of writing a constitution unfolds, it is likely to have reverberations across the region, said Nathan Brown, a professor at Georgetown University in Washington, DC.
"This isn't just about Egypt. It's turning a new path for the Arab world - a new democratic path for the Arab world," he said.