In Egypt, president's power grab unites those who once battled over Mubarak CAIRO - Supporters of former Egyptian leader Hosni Mubarak and the human rights advocates who dedicated themselves to toppling the longtime autocrat never dreamed they would find themselves chanting the same slogans. But with Egyptian President Mohamed Morsi's decision on Thursday to assume near-absolute power over his country, at least for now, secularists of all stripes have mobilized in ways unimaginable just a week ago. With Islamists largely backing Morsi, a battle is quickly taking shape over the degree to which religion will play a role in post-revolutionary Egypt's government. On Sunday, despite a nascent rebellion among the judiciary, Morsi's office said he would hold firm to his decisions. He also flexed his newly expanded powers for the first time, changing several labor laws by fiat. In a sign of fear about instability to come, Egypt's main stock index plunged by almost 10 percent on the first trading day since Morsi's announcement. It was the steepest drop since the turbulent days immediately after the revolution. Morsi's Muslim Brotherhood allies and his opposition plan to hold dueling demonstrations across the country on Tuesday in a bid to rally support, pro and con, in the biggest test yet of the power of each side to mobilize. With a new constitution set to be approved in the coming months, Tahrir Square - the heart of the revolution that toppled Mubarak - has in recent days become a rallying place for both liberal secularists and those who have scorned them as naive. Members of the long-suppressed Muslim Brotherhood, meanwhile, have been marshalling themselves in front of the very institutions once used against them. With many judges and prosecutors threatening a strike, Egypt has quickly been embroiled in a crisis that may threaten the democratic ideals of the revolution more than any other development in the tumultuous 21 months since Mubarak was deposed. In a measure of the topsy-turvy nature of the developing anti-Morsi coalition, idealistic liberal groups find themselves fighting the sidelining of a judiciary that in recent months has let many Mubarak-era officials walk away unpunished from charges of corruption and abuses. Meanwhile, law-and-order supporters of Egypt's military and police force find themselves dodging tear gas, shouting the same anti-government lines once used against Mubarak. The shifting lines were already on display in the June presidential elections, when Morsi narrowly beat Ahmed Shafiq, an emblem of the old guard, with just 52 percent of the vote. This time the common cause has new urgency, with Morsi removing the final check on his power by saying that courts do not have the right to review his decisions. The legislature was dissolved before he took office. Few among the opposition expect the coalition to be durable. Whether it will be enough to get Morsi to back down has yet to be seen. "New people who've never been to Tahrir, they went on Friday," said Hatem Farrag, 42, a businessman and charity operator who said his only other protest since the revolution had been last month to object to Morsi's first attempt to sack the Mubarak-appointed prosecutor general, Abdel Meguid Mahmoud. Liberals and Islamists alike have complained that Mahmoud was perverting justice to protect the old Mubarak elite and demanded his ouster. But when Mahmoud lost his job for good as part of the presidential announcement last week, liberal groups joined with protesters such as Farrag to object to the manner in which the prosecutor was pushed out.