The Muslim Brotherhood cancelled a large protest it had called in Cairo in support of Morsi, for fear the two groups would clash. Brotherhood demonstrations were reportedly planned for other cities, however.
On Nov. 24, dozens of political parties, opposition groups, and former presidential candidates announced that they would work together against the president's decree, and called for today's protest. Their ranks included popular figures such as Hamdeen Sabbahi, who garnered about 20 percent of the votes in the first round of presidential elections this year.
"It's kind of a new degree of coordination and new degree of unity that hasn't been done before. So it's kind of new uncharted territory," says Mr. Sabry, who adds that the opposition is focused on the president's decree, and not the president himself. "The question is how to keep the momentum rising, while avoiding any form of violence or unintended consequences."
Since the uprising, secular groups have exhibited not just divisions, but what critics call undemocratic tendencies. When Islamist parties won the majority of the seats, some secularists hoped for military intervention in the political process to weaken Islamists. Some also cheered when a court, backed by the military, disbanded the elected parliament. Secular parties sometimes appear more concerned with defeating Islamists than with plans for Egypt's future, say critics.
It's unclear whether Morsi's decree can mobilize the sheer numbers that would be needed to force him to back down, says H.A. Hellyer, a Cairo-based fellow at the Brookings Institution. The opposition likely lacks both the popular support or institutional backing needed to force Morsi to reverse his decision.