Egypt’s military chiefs are expected to issue a constitutional declaration redrawing the powers of the presidency before polls open Wednesday for the country’s first presidential vote since autocratic leader Hosni Mubarak was overthrown, according to state media reports.

The intent behind the move remained unclear, analysts said Friday. The generals might reduce the sweeping authority the constitution bestowed on Mubarak for three decades. Or they might act to cement their own considerable authority on the eve of a major transition.

As the candidates enter the final stretch of campaigning, the still-undefined power structure has cast a pall on what could be the most consequential election in Egypt’s modern history. The Islamists who dominate the country’s newly elected parliament have voiced support for a system with a weaker presidency, setting up a potentially bruising fight between lawmakers and the new president.

“It’s really anybody’s guess how these powers are going to be enumerated,” said Steven A. Cook, a foreign policy expert at the Council on Foreign Relations who has studied Egypt’s democratic transition closely. “It’s going to be a struggle between a parliament that can claim a popular mandate and a president who will also claim a popular mandate.”

Shortly after Mubarak’s ouster in February 2011, the military laid out a transition timetable that included drafting a revised constitution before a new president was sworn in. Efforts to assemble a body to draft the document that would have redefined the power structure have failed as a result of bickering between political factions and suspicion that the military council was underhandedly trying to shape the process.

Stephen McInerney, director of the Washington-based Project on Middle East Democracy, said the Supreme Council of the Armed Forces might issue a constitutional amendment that keeps the Mubarak-era system largely intact. But he noted that some have suspected the generals could have broader changes in mind. Under Mubarak, the military enjoyed elite status, and its budget and large commercial enterprises were not subject to scrutiny or criticism.

“There is some speculation that SCAF would limit the powers of the presidency and retain some key protection for themselves,” he said.

News of the council’s plan was reported on the English-language Ahram Online news service, which is run by the state, and by several local newspapers. The reports cited unnamed military officials.

The unresolved questions about the country’s power structure speak to the relative lack of progress the council has made toward laying the groundwork for a smooth transition to democratic governance since it abruptly took power after the winter revolt last year. Since then, the rise of Islamist political parties, spasms of violence and the military’s continued reliance on police-state tactics have created a culture of distrust and acrimony among Egypt’s ascendant powers.

While the contest that will culminate in the May 23-24 presidential vote is widely presumed to be a fair, open one, many Egyptians see it as just one more step in the ongoing struggle to dislodge the remnants of Mubarak’s government.

“I think most Egyptians have come to realize that the real issue is going to be how to dismantle the now famous apparatus of oppression and abuse that is still very much in power,” said Hossam Bahgat, a prominent human rights activist. “Egypt’s presidential election is going to have an impact on this fight only with regard to whether Egypt’s president is going to be with us or against us.”

Recent democratic transitions in the region have been turbulent. In Iraq, the presidency became a largely ceremonial post after the United States overthrew Saddam Hussein in 2003. In recent years, Prime Minister Nouri al-Maliki has sought to consolidate near-absolute power, although parliament retains considerable authority. In Afghanistan, where the United States was also heavily involved in shaping the transition, parliament has remained a largely toothless institution.

The main contenders in Egypt’s race have endorsed creating a system of checks and balances to steer the country away from its decades-long authoritarian course. The issue came up briefly during a debate between the two presumed front-runners, but it has not been a dominant campaign theme, nor has it emerged as a prominent voter issue.

The council’s declaration, if it is issued in coming days, would be superseded when and if a new constitution is drafted. Parliament is expected to soon appoint a 100-member body that will have six months to produce a draft, which then must be put before voters in a referendum.

Liberal politicians say members of the Muslim Brotherhood’s political arm, the Freedom and Justice Party, which holds the most seats in parliament, have deliberately avoided appointing the constitutional committee because they intend to calibrate their effort to enhance parliament’s powers depending on who wins. The party’s presidential candidate, Mohammed Morsi, is widely seen as a long shot.

“If they don’t win, they will fight until the end to have a parliamentary system,” said Mohamed Abou el-Ghar, head of the Social Democratic Party.

Mahmoud Ghozlan, the Brotherhood’s spokesman, called the military council’s move suspicious, saying it could be trying to make the new president stronger as a counterweight to parliament’s power.

“They want to make him as strong as the deposed,” he said, referring to Mubarak, who had the authority to dissolve parliament.

Perhaps the most contentious combination would come from a victory by former Muslim Brotherhood leader Abdel Moneim Aboul Fotouh, one of the front-runners. Brotherhood leaders deeply resent that the moderate Islamist broke ranks with the group to run for president. But parliament’s relationship with two other top contenders who held senior posts during the Mubarak era, Amr Moussa, a former foreign minister, and Ahmed Shafiq, a former prime minister, could also be strained.

Essam el-Erian, a prominent Freedom and Justice Party lawmaker, said the delay in appointing the constitutional committee reflected genuine disagreements rather than a sly strategy. But there was no question, he said, that Islamists in parliament would move quickly to strip down the powers of the president.

“I think everyone agrees that the president now has to be weaker than before,” Erian said. “In all world powers, parliament is a big power that stands up to the president.”

Special correspondents Ingy Hassieb and Haitham Mohamed contributed to this report.