MOSCOW — Russia’s seven-day national plebiscite, intended to keep President Vladimir V. Putin in power until at least 2036, delivered the expected verdict on Wednesday: Early results showed that three-quarters of voters had given their endorsement.

Less clear, however, was why Mr. Putin even needed voters to approve a raft of constitutional amendments that, already ratified by the national parliament in Moscow and regional legislatures across the country, entered into law months ago.

“From a juridical point of view, this whole exercise is insane,” said Greg B. Yudin, a sociologist and political theorist at the Moscow School of Social and Economic Sciences. But, he added, “it is not at all a meaningless procedure,” because Russia’s system under Mr. Putin depends on the appearance of popular support to confer legitimacy on decisions he has already made.

“It is theater, but very important and well-played theater. The system needs to stage displays of public support even when it doesn’t have it,” Mr. Yudin said. “This vote is putting Putin’s theatrical techniques to the test.”

In a final melodramatic flourish on Tuesday, Mr. Putin addressed the nation against the backdrop of monuments to Soviet soldiers killed fighting Nazi Germany, assuring voters that their voices mattered, no matter that the scores of amendments they were being asked to consider had already been enacted and the amended constitution had been published and put on sale in book stores. “The voice of each of you is the most important, the most significant,” Mr. Putin said.

Voters, in theory, could have rejected the amendments, and Mr. Putin pledged to honor their decision. But the chances of that happening always seemed minuscule, not least because of what Golos, an independent election monitoring organization, described on Tuesday as an electoral process rigged from the start. Read more via New York Times