CAIRO — The message blared from social media videos, from banners too big to miss, and from the upbeat Election Day songs playing so boisterously on jumbo speakers that they rose above the nonstop honking of Cairo traffic: “Do the right thing. Vote.”
On many of banners, a green checkmark next to President Abdel Fattah el-Sisi’s image demonstrated the proper way to vote. But even if not all of the messaging was explicit, it was clear enough what doing the “right thing” meant: Voting “yes.”
Saturday was the first of three days of voting in an Egyptian referendum on a series of constitutional amendments that, if passed as expected, will effectively extend Mr. el-Sisi’s hold on power eight years beyond his current term, until 2030.
They will also expand Mr. el-Sisi’s authority, along with the military’s, at the expense of the judiciary and legislature, placing top judicial officials under his control and allowing him to appoint some members of a new legislative chamber.
The changes — coming eight years after Arab Spring protests toppled the country’s longtime autocrat, Hosni Mubarak — will further strengthen Mr. el-Sisi’s authoritarian rule.
The protests in 2011 had initially ushered in a period of optimism among Egyptians who hoped for democratic change. But Mohammed Morsi, Egypt’s first freely elected president, was overthrown by the military amid fresh protests in 2013. And since then, Mr. el-Sisi has brutally squelched dissent, jailed thousands of opponents and further empowered the security services and the military.
Elections, too, have come to resemble the votes of an earlier era.
Just as in the landslide victory in which Mr. el-Sisi won a second term last year, the outcome of this referendum is not hard to predict, though many civil society organizations urged people to vote “no” and Egyptians living overseas publicized their “no” votes on social media.
The question was less whether the amendments would pass but more whether a high turnout would allow the authorities to cast them as broadly popular.
“An election that has more participation is an election that looks more legitimate,” said Mai El-Sadany, the legal and judicial director of the Tahrir Institute for Middle East Policy in Washington.
“You’re seeing the state, all of its apparatuses and its allies working toward both getting people to the street and getting people to vote ‘yes,’” Ms. El-Sadany added. “On the flip side, you’re not seeing a space for the ‘no’ vote to mobilize.”
Two members of the National Election Authority did not respond to requests for comment. But on Saturday, all signs suggested that the authorities were not leaving a high turnout to chance.
Zigzagging through the chaotic Cairo streets, minibuses and tuk-tuks carried signs advertising free rides for anyone going to the polls. The back windows of buses bore green checkmarks.
At a corner kiosk selling snacks on the east bank of the Nile, a large banner over the entrance proclaimed the owner’s support for Mr. el-Sisi and the constitutional amendments. A store employee, Mohamed Abdel Aziz, said the police had visited and told the owner to put up the sign.
Near polling stations in poor neighborhoods, workers handed out cardboard boxes packed with free groceries — usually a mix of cooking oil, sugar, ghee, lentils or rice — to people who could prove they had voted.
Walking down the street on her way to the polls in the Rod el-Farag neighborhood, Neama, a widow with four children, said she did not know what the referendum was about, but planned to vote in order to get the subsidy box.
It was much the same with other women interviewed near polling stations on Saturday: They knew little about the measures, they said, but the promised benefits were too good to pass up. Most voters interviewed on Saturday declined to give their names, nervous about the potential repercussions of speaking to journalists.
But like many in Cairo’s poorer areas, those interviewed also were not averse to having Mr. el-Sisi extend his term.
A local businessman known as Abu Halawa turned a dusty side street into a referendum party of sorts, covering it in signs with directions to vote. As songs about voting blasted from the speakers, people lined up to collect coupons. If they got the coupons marked after voting, several people said, they could redeem them for as much as 200 Egyptian pounds, less than $12.
The referendum started just four days after Egypt’s House of Representatives approved the constitutional changes. With the government having muffled criticism of the amendments, many Egyptians heard little about any position other than voting in favor.
Opposition figures were barred from participating in debates about the amendments. The authorities canceled a scheduled protest a few weeks ago, citing national security, then blocked several websites belonging to groups that tried to mobilize opposition. Two Egyptian actors who had publicly criticized the amendments were suspended by their union.
At the same time, several well-known Egyptian singers recorded get-out-the-vote songs in support of the changes, and official social media channels and state-controlled media ran public service announcements about voting “yes.”
Still, it is clear that the president enjoys support in many quarters, from those who say he offers security in a turbulent region.
“I only vote when Sisi is involved,” Mamdouh Mikhail, a blacksmith who supports the president’s economic program, said on Saturday. “I support Sisi for life.”