Russian President Vladimir Putin. (Mikhail Klimentyev/Sputnik, Kremlin Pool Photo via Associated Press)

IN AN open society, public opinion polling is essential to connect the rulers and the ruled. To borrow a cliche, polls speak truth to power. This is much harder to do in a closed society where people are afraid to speak their minds. In recent years, Russian President Vladimir Putin slowly eliminated free-thinking news media and extinguished civil society groups, but the Levada Center managed to survive as an independent polling organization. Its studies of Russian public opinion have been penetrating, and that explains why it is now faced with suffocation.

For more than a decade, the center founded by Yuri Levada has been known as a superior source of research on what Russians are thinking, untainted by Kremlin influence. The polls, never easy to carry out in a public unaccustomed to free speech, have charted the ups and downs of post-Soviet life, including the genuine high popularity of Mr. Putin in the years of high oil prices and relative stability.

But in recent times, the center has also documented the underside of Mr. Putin’s tenure. In an essay titled “Putin’s Relapse Into Totalitarianism,” the director, Lev Gudkov, wrote last year that 10 to 12 years of repressive, domineering rule has “sterilized” Russia’s public space, leaving people with nowhere to articulate their interests and work out their problems. Mr. Gudkov said Mr. Putin was taking Russia toward dictatorship, with dire consequences for the economy and the nation’s future.

At the same time, Mr. Gudkov showed that Russians are well aware of the Putin cabal’s self-aggrandizement. In a survey in January 2014, Russians were asked, “What traits do you think are most characteristic of the majority of modern Russian politicians?” Forty-four percent said “unscrupulous lust for power,” and 41 percent said “greed,” while 1 percent said their leaders had “high morals.” Mr. Gudkov concluded that Russians “are convinced that the current rulers are mainly concerned with the preservation of their own power and personal enrichment rather than the prosperity of the country.” Levada Center polls in advance of the parliamentary vote Sunday show public disenchantment with the ruling party, United Russia.

Not surprisingly, the regime struck back and recently labeled the Levada Center a “foreign agent.” The Levada Center is a nongovernmental organization that has often worked on surveys with overseas partners, such as the University of Wisconsin at Madison. The designation as “foreign agent” could be a death knell for the Levada Center. “There are fears lingering since the Soviet times [that] ‘foreign agent’ means a spy or a saboteur to most Russians,” Mr. Gudkov told Bloomberg News. Will Russians share their honest feelings with a pollster carrying such a label? Not likely.

Like all tyrants, Mr. Putin basks in the conceit that he is a beloved leader and can do no wrong. Mr. Gudkov’s polls have suggested all is not well in Putinland. The Levada Center helped Russians speak truth, and that is why the organization is now being told to shut up.