Protests erupted across Egypt on Friday, as opponents of President Mohamed Morsi clashed with his supporters over a presidential edict that gave him unchecked authority and polarized an already divided nation while raising a specter, the president’s critics charged, of a return to autocracy.
In an echo of the uprising 22 months ago, thousands of protesters chanted for the downfall of Mr. Morsi’s government in Cairo, while others ransacked the offices of the president’s former party in Suez, Alexandria and other cities.
Mr. Morsi spoke to his supporters in front of the presidential palace here, imploring the public to trust his intentions as he cast himself as a protector of the revolution and a fledgling democracy.
In a speech that was by turns defensive and conciliatory, he ultimately gave no ground to the critics who now were describing him as a pharaoh, in another echo of the insult once reserved for the deposed president, Hosni Mubarak.
“God’s will and elections made me the captain of this ship,” Mr. Morsi said.
The battles that raged on Friday — over power, legitimacy and the mantle of the revolution — posed a sharp challenge not only to Mr. Morsi but also to his opponents, members of secular, leftist and liberal groups whose crippling divisions have stifled their agenda and left them unable to confront the more popular Islamist movement led by the Muslim Brotherhood.
The crisis over his power grab came just days after the Islamist leader won international praise for his pragmatism, including from the United States, for brokering a cease-fire between Hamas and Israel.
On Friday, the State Department expressed muted concern over Mr. Morsi’s decision. “One of the aspirations of the revolution was to ensure that power would not be overly concentrated in the hands of any one person or institution,” said the State Department spokeswoman, Victoria Nuland.
She said, “The current constitutional vacuum in Egypt can only be resolved by the adoption of a constitution that includes checks and balances, and respects fundamental freedoms, individual rights and the rule of law consistent with Egypt’s international commitments.”
But the White House was notably silent after it had earlier this week extolled the emerging relationship between President Obama and Mr. Morsi and credited a series of telephone calls between the two men with helping to mediate the cease-fire in Gaza.
For Mr. Morsi, who seemed to be saying to the nation that it needed to surrender the last checks on his power in order to save democracy from Mubarak-era judges, the challenge was to convince Egyptians that the ends justified his means.
But even as he tried, thousands of protesters marched to condemn his decision. Clashes broke out between the president’s supporters and his critics, and near Tahrir Square, the riot police fired tear gas and bird shot as protesters hurled stones and set fires.
Since Thursday, when Mr. Morsi issued the decree, the president and his supporters have argued that he acted precisely to gain the power to address the complaints of his critics, including the families of protesters killed during the uprising and its aftermath.
By placing his decisions above judicial review, the decree enabled him to replace a public prosecutor who had failed to win convictions against senior officers implicated in the killings of protesters.
The president and his supporters also argued that the decree insulated the Constituent Assembly, which is drafting the constitution, from meddling by Mubarak-era judges.
Since Mr. Mubarak’s ouster, courts have dissolved Parliament, kept a Mubarak loyalist as top prosecutor and disbanded the first Assembly.
But by ending legal appeals, the decree also removed a safety valve for critics who say the Islamist majority is dominating the drafting of the constitution.
Mr. Morsi and the Muslim Brotherhood, the movement he once helped lead, both frustrated with their inability to build consensus, have been accused of conveniently dismissing critics of all types as loyalists of the former government.
In an interview this month, Essam el-Erian, the vice chairman of the Brotherhood’s Freedom and Justice Party, said as much, asserting that the “the majority” of secular or liberal opposition figures were in fact Mubarak loyalists.
Mr. Morsi was more forgiving of the opposition on Friday, saying that he wanted a “real opposition with awareness” while raising the threat of meddling by foreign enemies and a “few” Mubarak loyalists.
Another article in Mr. Morsi’s decree, that gives him broad powers to confront unspecified threats — including to “the revolution” — has played into decades-old fears of the Brotherhood as an insular, authoritarian movement shaped by decades as an underground secret society.
But Mr. Morsi may have miscalculated the public’s support for the courts, which include judges seen as independent and who have taken stands against both Mr. Mubarak and the Brotherhood.
In Tahrir Square on Friday, derision for the Brotherhood and Mr. Morsi’s decision was widespread. The Brotherhood’s members were called American agents by one group of chanters, and fundamentalists bent on turning Egypt into Afghanistan by another.
One sign melded Mr. Morsi’s face with a youthful picture of Mr. Mubarak. “Mohamed Morsi Mubarak,” it said.
“They believe only in Islam,” said Dr. Ali Abdul Hafiz, a former Brotherhood member and now a strident opponent of the group. “Our affiliation is with our country. We want a modern state. How can we believe the Muslim Brotherhood will take it for us?”
As he spoke, some of Egypt’s leading opposition figures entered the square, including Hamdeen Sabahi, a charismatic Nasserist politician, and Mohamed ElBaradei, a former top United Nations nuclear official. Earlier in the day, the two men had joined other prominent figures in a rare show of unity that belied a record of divisions that have rendered the secular-minded opposition largely incoherent.
In the last parliamentary elections, Islamists won 75 percent of the seats. The Parliament was dissolved, but its influence remains in the Constituent Assembly, which is dominated by those who are from parties based on political Islam. Despite repeated complaints about the tenor of the constitution, Mr. Morsi’s weak opponents have found no way to derail its progress.
But Mr. Morsi’s secular opponents, too small a minority to vote down the charter, have resorted to threats of a boycott to delay or influence it, and within the past week as many as a quarter of the Assembly members walked out to protest a rush by Islamists to complete the work.
But on Friday, sensing a moment of overreach by Mr. Morsi, his critics have found new energy. Omar Ashour, a professor of Arab politics at the University of Exeter in Britain, suggested that it was unlikely the opposition would quickly yield. “At this point, I don’t see the 60-year-plus heads of parties are in the mood to talk,” he said in an e-mail analyzing the crisis. “They’d rather show strength via their youth in the streets.”
Mr. Morsi’s supporters acknowledge that the administration made a mistake in presenting his decree, without first reaching out to his opponents. Even the president’s advisers were blindsided: one adviser, Samir Morcos, told the state newspaper that he learned of Mr. Morsi’s decree on television. He was reported to have quit in protest.
On Friday the president tried to paper over the differences by focusing Egyptians on the future.
“I don’t seek to grab legislative power,” Mr. Morsi said. “We’re moving on a clear path, we are walking in a clear direction. And we have a big, clear goal: the new Egypt.”