CAIRO (Reuters) - After six decades under the thumb of men from the military, Egyptians savour the novel experience this week of a presidential election whose outcome no one knows in advance.
They vote on Wednesday and Thursday for a leader to replace Hosni Mubarak, who was swept away 15 months ago by a popular revolt that ushered in a turbulent military-led transition and elections for a parliament now dominated by Islamists.
No real power has yet changed hands. An army council led by the man who served as Mubarak's defence minister for 20 years still holds the reins, promising to hand over by July 1 after a new president is elected, probably in a run-off vote in June.
Opinion polls are untested. Previous post-Mubarak votes - the parliamentary poll won by the Muslim Brotherhood trailed by its hardline Salafi rivals, and an earlier referendum that overwhelmingly approved army-proposed interim constitutional changes opposed by liberals - may be no guide this time round.
Like other Arab states where pent-up rage from political and economic frustrations erupted last year, Egypt is struggling to define its future after its dazzling moment of promise.
Months of tussles and fluid alliances involving the army, Islamists, protesters and others have bewildered many Egyptians and disillusioned some of the young people who helped topple Mubarak.
Many hope their country can one day regain its primacy in the Arab world, effectively lost when then-President Anwar Sadat signed a peace treaty with Israel in 1979 and the most populous Arab nation became a linchpin of Washington's Middle East policy and the biggest recipient of U.S. military aid after Israel.
But the overwhelming, urgent challenge for the new president will be to revive an economy battered by months of unrest and uncertainty, and to remedy the poverty, unemployment and collapsing public services that helped fuel last year's revolt.
No one can safely predict which of the dozen candidates will win, in itself a refreshing change after the tiresome electoral charades played out in Mubarak's 30 years of autocratic rule.
More disturbingly, no one can predict what powers the president - or parliament or the military or the courts - will wield, given Egypt's failure so far to write a new constitution.
"UP IN THE AIR"
"The constitutional relationship is entirely up in the air," said Rashid Khalidi, Arab studies professor at New York's Columbia University. "This is the biggest question in Egypt. It's not Muslim fundamentalist or not, or Muslim Brotherhood or not, it's parliament or the presidency and where power really resides."
The generals, accustomed to laying down the law to civilians, deny any desire to run Egypt's day-to-day affairs, but few doubt their ambitions to retain the military's vast privileges and to secure a powerful say behind the scenes.
The confusion may persist, but politicians planned to meet on Monday to discuss possible temporary constitutional changes to recommend to the ruling military council, which could issue a decree regulating the powers of the president and parliament.
For now, all eyes are on the vote, mostly pitting Islamists against more secular figures, notably former Arab League chief Amr Moussa, who was previously Mubarak's foreign minister, and the deposed leader's last prime minister, Ahmed Shafiq.
Moussa and Shafiq are likely to win many votes from the Christians who make up about a tenth of Egypt's 82 million people and who fear the implications of rising Islamist power.
One Islamist, Abdul Moneim Abol Fotouh, has wooed liberals and ultra-orthodox Salafi Muslims. The leftist Hamdeen Sabahy touts his record as a veteran campaigner for workers' rights.
The electoral commission, led by a former military man, had barred Shafiq from the race last month, but he won an appeal. Other candidates disqualified included a Salafi and the Muslim Brotherhood's first-choice contender, Khairat al-Shater.
Anyone who doubts the Brotherhood has shed its political reticence should have attended its boisterous final campaign rally in the heart of Cairo on Sunday night.
Under Mubarak, the Islamist group preached a patient, gradualist approach, seeking to avoid persecution and making only limited stabs at contesting routinely rigged elections.
Even after Mubarak fell, the Brotherhood said it would not fight all parliamentary seats and would not seek the presidency - promises it broke in the heady lure of power.
In Abdeen Square, it mobilised thousands to cheer and chant for its lacklustre reserve candidate, Mohamed Mursi, who took to the stage amid flames, fireworks and frenzy whipped up by a phalanx of youths in white T-shirts and red headbands.
The U.S.-educated engineer promised to combat any corrupt Mubarak-era remnants who might try to "take us backwards" or tamper with the election or security. "We know who they are," he shouted. "We will throw them in the rubbish bin of history."
(Editing by Giles Elgood)