Mohamed Sayyed Tantawi, a prominent economist, had stayed up all night, watching the scenes unfold on television in Tahrir Square. “With all of these people,” he said, “I thought this must be the birth of a new era.”

Others, however, were skeptical. Mr. Tantawi, then the head of the ruling Supreme Council of the Armed Forces, convened top commanders in the morning to look over what they had witnessed the night before. The commander who put his face in his hands and cursed wasn’t exaggerating, he was told.

“They’re calling it ‘the night of martyrs,'” Mr. Tantawi remembers hearing. “And I said, ‘What have we been fighting for?’ They were saying they had been fighting for a new life, a new life. And I thought, ‘Really, we fought for this?'”

But after Hosni Mubarak had resigned as president of Egypt, along with the top brass of the army, and the military government had resigned, and Mr. Tantawi and others had served as prime minister, deputy prime minister and minister of defense, his head could hardly have been blunter: “We did what we were told.”