This is where the current movement led by Mr. Navalny differs from the 2011 and ’12 protests. Alongside his anti-corruption message, he has developed a “smart voting” strategy designed to draw voters to whichever candidates are best placed to beat United Russia incumbents, turning scattered protest votes into a more targeted rejection of the status quo.

First tried out in local elections in 2019 and deployed again last year, the strategy’s gains so far are hard to gauge — but it represents a novel challenge to Mr. Putin and his party. United Russia is polling at about 30 percent and will be looking nervously over its shoulder: Elections to the national parliament are due in September.

There is plenty of fuel for unrest. Average disposable incomes in Russia dropped by more than 10 percent from January to September of last year, as the pandemic sent an already sluggish economy into downturn. Living standards remain stubbornly low: In 2020 nearly 20 million Russians were below the official poverty line. In this context, Mr. Navalny’s anti-corruption message — in particular, his videos detailing the luxuries that the country’s rulers have lavished on themselves at the taxpayers’ expense — has hit home.