Now, however, the Brotherhood is freely exercising its organizational muscle. Since Mubarak was run out of office, the Muslim Brotherhood has opened offices in every province. It has its own satellite television network in the works, which reportedly will be called Egypt 25 and could launch in June. It has entered coalition talks with other groups. Its new political party claims a Coptic Christian vice president, though that move has done little to assuage worries among Egyptian Christians and secularists.
In truth, the Brotherhood's top leaders are accustomed to operating in secrecy, and they resent the doubts of their secular political opponents as much as they do the pushback they face from their own younger members. The supreme guide of the Brotherhood has drawn criticism in recent months for his view that women and Christians should not be allowed to serve as president of Egypt and for backing the incorporation of sharia punishment into Egyptian criminal law.
These positions -- anathema to many Egyptian centrists who still consider themselves religious -- have fed a growing anxiety that the Brotherhood will hold a dominant position in the political pecking order. According to a Gallup poll released this week, only 15 percent of Egyptians say they support the Muslim Brotherhood. That's slightly better than the National Democratic Party, Hosni Mubarak's party, which 10 percent of respondents said they support.
At first, the Brotherhood said it would contest only 30 percent of the seats in parliament, and wouldn't run a presidential candidate. In late May it raised the ante, now saying it will compete for half the parliamentary districts.
The opening of the new official headquarters in Moqattam dramatically punctuated the Brotherhood's transformation. Bright lights illuminate the party logo in English and Arabic -- a pair of green crossed swords.
About a hundred movement activists prayed outside before the official opening (the building's been in use for months already). They chanted the Brotherhood motto in unison:
God is great.
The Prophet is our teacher.
The Koran is our constitution.
Jihad is our way.
Martyrdom is our goal.
Then they stormed into the building and emptied trays of fruit juice.
In a sign of the Brotherhood's political heft, a parade of notables came to pay respects, including presidential front-runner and former Arab League chief Amr Moussa and a coterie of other secular politicians and judges.
In a rear lot behind the headquarters, more than a thousand supporters assembled in a dirt lot covered with carpets for the occasion. A band sang paeans to freedom, brotherhood, and the Brotherhood.
Khairat Shater, a millionaire and the number-two official in the Brotherhood credited with being one of its most powerful fixers, grinned just beside the stage.
"Where do you think state security is now?" I asked. At the last Brotherhood function I attended, an iftaar in the parliamentary offices in August, the number of plainclothes intelligence officers hovering around the event equaled that of the Brotherhood officials inside.
"They haven't gone home," he said. "They're around here somewhere."
If one were keeping score, however, the Brotherhood would look to be ahead.