Judges have dismissed many charges originally brought against Mr. Mubarak, including directing the killing of protesters. But the previous post-Mubarak governments always made clear that they would keep finding new allegations to keep the former leader behind bars. The council of generals that succeeded Mr. Mubarak was too desperate to placate the public and preserve its own legitimacy to release him, and Mr. Morsi campaigned on promises to keep him locked up.

But the Sisi government has no such insecurity about its power, or hostility to Mr. Mubarak. Some members of political factions that had previously joined rallies for Mr. Mubarak’s incarceration, or even execution, said they believed the public did not care so much anymore.

“I don’t think people are paying the slightest attention,” said Hussein Gohar, a spokesman for the Social Democratic Party. “And if it happens, it will not have anything close to the impact it would have had a year ago,” he said of Mr. Mubarak’s release, in part “because people have moved on” and in part “because of the paradigm shift to support for the army.”

Besides, Mr. Gohar said, he did not think the new military-backed authorities would allow massive protests against Mr. Mubarak, once an Air Force general. “At the end of the day, Mubarak is part of the military,” Mr. Gohar said. “He is one of them.”

The interim government bears other resemblances to the Mubarak government. General Sisi, the defense minister, was Mr. Mubarak’s head of military intelligence. The figurehead president, Adli Mansour, a judge, was appointed to a top court under Mr. Mubarak. The interior minister was a high-ranking official under Mr. Mubarak. The foreign minister is a senior ambassador who served in Washington. The finance minister is an economist who worked closely with Mr. Mubarak’s son and designated successor, Gamal, who became a senior figure in the old ruling party. And the justice minister is another judge appointed to a top court under Mr. Mubarak.

But many pointed to crucial differences between now and the Mubarak era.

Mr. Gohar of the Social Democrats said the revolution had inculcated a new demand for participation and accountability that would prevent a return to the old order. “There is still a deep state, of course, but you cannot go back,” he said, adding that continued pro-Morsi protests demonstrated Egyptians’ new assertiveness. “People are not going to be passive anymore and just accept what is handed to them by the government.”

Mr. Bahgat argued that General Sisi’s government might rely on the same people, institutions and tactics that Mr. Mubarak did, but said it was a new authoritarianism, not a restoration. This time, he said, there is a much greater emphasis on “the propaganda machine,” suggesting that attention to public opinion may be the main legacy of the 2011 revolt.

Many analysts say that whatever its inclinations, the government is unlikely to risk even a small public backlash at this volatile moment by releasing Mr. Mubarak. If it does not, his continued incarceration opens the intriguing possibility that he and Mr. Morsi, now detained at an unknown location, might end up in jail together. Mr. Morsi is no stranger to jail: he was there as a political prisoner just before Mr. Mubarak’s ouster.