CAIRO — Deep divisions among voters and politicians under a climate of uncertainty threaten political stability as Egypt lurches toward electing its first contested presidential election this weekend.

Egyptians will be electing a president whose powers have yet to be determined, since the constitution was suspended by the Supreme Council of Armed Forces (SCAF) when it took control from ousted president Hosni Mubarak; and a new one has not yet been written.

A sign of political progress last week among parliament was short-lived. After three months of deadlock, under a SCAF-issued ultimatum, the Islamist-majority parliament agreed last Thursday to designate half of the 100-member constitution-writing panel’s seats for liberal and secular representatives.

But by Sunday night, secular lawmakers had walked out of a meeting called to name the representatives who would draft the new constitution. They accused the Muslim Brotherhood’s Freedom and Justice Party, and the Salafist Al-Nour Party, who together won over 70 percent of the seats in parliament, of filling all 50 seats designated for Islamists, so that the smaller Islamist parties were vying for the seats meant for representatives of the secular parties and civil society institutions.

Sunday’s walkout against Islamists was not the first by liberal parliamentarians this year. The parliament has been suspended since April when liberals boycotted it in protest of what they perceived to be the Islamists’ abuse of power.

Failure of the Muslim Brotherhood’s presidential candidate, Mohamed Morsi, to garner more than one-quarter of the vote in the first round of balloting is widely seen as a dramatic loss of trust in a party that showed so strongly among their base and the revolutionary voting bloc in parliamentary elections last fall.

Architect Karim El Hayawan told The Media Line that it was the Muslim Brotherhood’s unwillingness to compromise and the numerous promises it has broken since Mubarak’s overthrow that had him wary of its initial run for parliament.

Now, with the legality of the parliament itself at risk of being overruled by Egypt’s Supreme Constitutional Court this Thursday — just two days before their candidate faces off against former Mubarak prime minister and confidant Ahmed Shafiq in the presidential runoffs — El Hayawan says the Brotherhood is being more reckless with its power.

“The Muslim Brotherhood started out ravenous for power and has ended up being cornered into a life-or-death defensive,” says El Hayawan. “With parliament’s very fragile legal status, it’s not greed alone that’s driving the Brotherhood anymore,” he says.

If Shafiq wins, El Hayawan thinks the historically persecuted Brotherhood fears being forced to go back to life underground, especially now, with no guaranteed support, and intense opposition from, the revolutionary voting bloc. Therefore, the constitutional panel remains “the only valid pressure card” for the Brotherhood to play, El Hayawan explains. The constitution will also define the powers of the parliament, the relationship between religion and the state, and the role of the military in politics.

Egypt’s judicial branch may also blur the lines on the country’s roadmap to democracy. Two days before the presidential runoffs, scheduled for June 16 and 17, if the court rules last year’s parliamentary elections to have been unconstitutional, parliament will be dissolved and Egyptians will have to vote again.

The court will also rule on the legality of Shafiq’s candidacy. The current parliament had passed a political isolation law barring former top Mubarak-regime officials from holding public office for a period of ten years. Egypt’s Presidential Election Committee granted Shafiq and exception, allowing him to remain in the race.

El Hayawan predicts that the instability is just beginning, with SCAF being the only power in control. “We are in for a long, tedious battle, with two remaining game changers,” he told the Media Line.

“SCAF has been able to keep it all unpredictable until the last minute,” El Hayawan said. “It might be a way to pressure both candidates in return for guarantees of power. Even Shafiq. SCAF trusts no one.”

Meanwhile, protesters who see a Shafiq presidency as the continuation of military rule are sharply divided between those supporting Morsi and others campaigning for a boycott of the elections, at times coming to blows in Tahrir Square.

Middle East political analyst Sana Saeed told The Media Line that such divisions are worrying, but not unsurprising.

“It’s unsurprising because a revolutionary atmosphere easily polarizes, especially when the old guard is vying for positions of power and representation,” explains Saeed.

“It’s concerning, however, because escalation of these divisions can hurt the Egyptian populace itself.”

Saeed cautions Egyptians to focus on the big picture. While Egyptians know that “SCAF is still fully in control, the divisions that have emerged threaten to distract from that,” she said.

Ultimately, Saeed thinks that “Egyptians have shown themselves as unwilling to take any more authoritarian rule lying down.” But she worries that “violence will escalate as divisions become more pronounced and SCAF struggles to hold onto its power.”