Sunday in Moscow was a bright spring day, chilly but clear, and by the time I made my way to Tverskaya Street, Moscow’s main thoroughfare, the sidewalks were full of people strolling up, toward Pushkin Square, and down, toward Red Square and the red-brick towers of the Kremlin. They had come out for a march led by Alexey Navalny, Russia’s savviest and most popular opposition politician, who had declared a nationwide day of anti-corruption action. The protest was one of mere presence, rather than any specific activity: a few people held signs, and every now and then a chant broke out, but the main political statement of the day was simply showing up.

The nominal cause for the march, and for similar gatherings in dozens of cities across the country, was alleged corruption that Navalny and his researchers had unearthed about Dmitry Medvedev, Russia’s largely enfeebled Prime Minister. Earlier this month, Navalny had published a report detailing various far-flung properties, luxury yachts, and other high-end goods that Medvedev has allegedly acquired over the years, in part funded by contributions that Russian oligarchs made to fake charity foundations. But Sunday’s demonstrations were also about a creeping mood of public dissatisfaction and fatigue, a sense that, after seventeen years, Vladimir Putin’s political system was running out of arguments to justify its continued monopoly hold on power. Official corruption proved to be a more compelling rallying cry than civil rights or voting irregularities: less about abstract political freedoms and more about the insult of learning that your country’s Prime Minister had acquired a vineyard in Tuscany while disposable incomes dropped an average of twelve per cent since 2014.

The Moscow mayor’s office had not authorized the march route—it had instead offered organizers the use of a park outside the city center—and had cautioned that it could not “bear responsibility for any possible negative consequences” of the unsanctioned demonstration. The warning didn’t seem to keep people away. On Tverskaya, it was impossible to judge the size of the crowd, but it was easily several thousand. The official response seemed chaotic and inconsistent. Most people walked unimpeded up and down the street for hours. But Navalny himself was grabbed and thrown into a police van a few minutes after he arrived, with a pair of Nike sneakers hanging from his neck—a riff on one of the charges that he had levelled against Medvedev, who he said used a front company led by a loyal crony to buy himself running shoes.

Near the Central Telegraph building, where I stood, the flow of people passed unbothered, but by Pushkin Square riot police, wearing black body armor and helmets, arrested dozens of people, clubbing and beating them before dragging them away. By the end of the day, as many as a thousand people in Moscow had been detained, far more than in 2011 and 2012, the last time the capital saw demonstrations of this size. A reporter from the Guardian was caught up in the arrests; he was taken to a police station and charged with “holding an unsanctioned rally.”

I was struck by how many young people had joined the protest march. During the previous wave of large-scale demonstrations in Moscow, the crowds were largely drawn from the capital’s middle class—educated, professional people in their twenties, thirties, and forties. On Sunday, the presence of high schoolers and college students was immediately noticeable. “Never before have schoolchildren and students participated on such a massive scale in opposition protests,” Meduza, an independent news site that is home to some of Russia’s best journalism, declared. “Teen-agers easily experience feelings of envy, unease, of being trivialized—and they go out and they try to do something,” a seventeen-year-old, named Konstantin, told the site, explaining why he joined the demonstration.

In explaining Putin’s consistently high approval ratings, many analysts and journalists point to the fact that more than eighty per cent of Russians receive their news from state-television broadcasts. Younger Russians, though, are less likely to pay attention to state-controlled TV, and it seems that the Kremlin has less certain tools for reaching this demographic, let alone shaping its political attitudes. Even LifeNews, a usually servile, pro-Kremlin tabloid site, has admitted this new reality. In an article published on Monday, called “Farewell, Television,” a Life columnist acknowledged that “television, by focussing on the adult, even elderly, part of the population, completely missed the active and young audience.” Sunday’s protests, in the columnist’s view, represented an “extremely disturbing and serious warning sign” for Kremlin officials. “Television has failed, and its inefficiency as a mass ‘agitator and organizer’ will only intensify.”

Russia’s young people can truly be called “Putin’s” generation: those under twenty-five have no significant memories of any other Russian leader. Yet, as was the case during perestroika, in the nineteen-eighties, the authorities appear to have lost a certain sway over the country’s youth, and no longer speak their language. Two weeks ago, a remarkable video of a meeting between a principal and high-school students in Bryansk, a provincial city some two hundred miles from Moscow, surfaced online, and was widely shared. The students had been hauled in for a lecture after one of them had urged his classmates to attend the local version of Navalny’s anti-corruption protest.

The principal’s tone is hectoring and frustrated. “What Navalny is doing is a pure provocation. Do you get it? You still don’t understand this,” she tells the students. They push back against her claims. One says, “We basically took it,” referring to Crimea. Another tells her about evidence of Russian troops in eastern Ukraine: “There are videos going around—you have no idea.” The argument goes in circles, with the principal trying to scare the students with talk of civil war and unrest, and the students answering her with talk of “justice,” or what one describes as “when the authorities care about their people, and not just about themselves; when they care about ordinary citizens, and not about their millions of dollars.” Losing her patience, the principal asks whether Putin and Medvedev have made life worse. No, a student answers, “but they’ve stayed too long.” Neither side convinces the other, but it is the students who sound more confident and clearheaded in their arguments; the principal’s voice is marked by a note of disorientation, the frustration of falling behind the times and no longer enjoying the easy authority she once had.

For the Kremlin, the geographic diversity of Sunday’s protests was just as unsettling as their demographics. Gatherings of various sizes were held in nearly a hundred Russian cities, including places where demonstrations hadn’t occurred five years ago, during the previous wave of anti-Kremlin protests. A couple of hundred people came out in Nizhny Tagil, an industrial stronghold in the Ural Mountains where, in 2011, factory workers had volunteered to travel to Moscow and, if necessary, use force against anti-Putin protesters. More than a hundred and fifty people were detained in Makhachkala, the capital of Dagestan, a republic in the North Caucasus where Putin got more than ninety per cent of the vote in 2012. It was clear that the Kremlin hadn’t anticipated anti-government activity in such regions, and that it had failed to give clear instructions to local authorities. As a result, in some places, the protests went on unmolested; in others, they were broken up roughly, as in Omsk, where authorities had snowplows drive out the crowd in the city’s central square.