“It’s been true for several years now that the gains of 2011 have been lost,” said Michele Dunne, the director of the Middle East program at the Carnegie Endowment for International Peace in Washington. “But I think that this just makes it more and more clear to people.”

With the outcome never in doubt, the government and its allies were eager to lift turnout, the better to show that Egyptians were not merely in favor of the amendments, but enthusiastic.

Voters interviewed in working-class parts of Cairo said they had received free boxes of pantry basics like sugar and cooking oil. In some cases, voters said they were promised small amounts of cash for voting. One hotel, the Sonesta, advertised a raffle during the referendum: Vote, and you will be entered in a raffle to win a free trip to Mecca — a pilgrimage that all Muslims are supposed to make.

People were required to prove only that they had voted, not that they had voted yes, to receive such benefits. But driving around Cairo over three days of national voting, it was usually hard to tell that there were two sides to the ballot.

Banners draped over the streets — including some that the police had coerced shopkeepers into putting up — endorsed Mr. el-Sisi and the constitutional changes. Patriotic songs by well-known singers urged voters to the polls to “do the right thing,” and minibuses emblazoned with affirmative green check marks drove them there free.

Before and during the vote, the opposition was nowhere to be seen in the Egyptian news media. Opposition websites were blocked, and a scheduled protest against the amendments was canceled by the authorities.