Russian President Vladimir Putin addresses students during a visit to the German Embassy school in Moscow on June 29. (Alexander Zemlianichenko/Associated Press)

HARD TO believe, but a court in Perm, a Russian city near the Ural Mountains, recently convicted Vladimir Luzgin, 37, and fined him 200,000 rubles, or about $3,100, for posting a simple and true historical fact. Mr. Luzgin wrote on Vkontakte, a Russian social media platform like Facebook, that the Soviet Union collaborated with Nazi Germany to invade Poland in September 1939. He was prosecuted under a law signed by President Vladimir Putin in May 2014 against “rehabilitation of Nazism,” a law that declared its intent was to oppose glorification of Nazism but that human rights activists say was intended to discourage historical debate.

The Soviet Union long tried to hide the secret protocols to the 1939 Molotov-Ribbentrop pact, which divided up Poland and the Baltic states between Germany and the Soviet Union. Moscow admitted the protocols were genuine only in Mikhail Gorbachev’s glasnost years. More recently, a motif of Mr. Putin’s rule has been to buff Stalin’s legacy and fuzz up his collaboration with Hitler. Last year, Mr. Putin openly defended the Molotov-Ribbentrop pact, saying it was necessary for the times; culture minister Vladimir Medinsky called it a “colossal achievement of Stalin’s diplomacy.”

Mr. Luzgin’s posting might have gone unnoticed but for the desire of the Russian authorities to make an example of him. As Professor Mark Galeotti of New York University wrote recently, Mr. Putin has not reinstated mass repressions like those of the Stalin era, but rather relied on “a relative handful of well-publicized spectacles of brutish state persecution.” This makes everyone wary all the time, Mr. Galeotti wrote, carrying “a little censor, a micro-Putin” around with them.

For those not carrying a micro-Putin, the Kremlin has other means. On July 7, Mr. Putin signed a law requiring telecom operators to store recordings of customer phone calls and text messages for six months for perusal by the security services, and messaging services such as Facebook and Telegram to provide encryption keys to the authorities on demand. In today’s Russia, Big Brother is watching, again.

In China, which blocks sites such as Facebook and Twitter that are outside its Great Firewall, social media inside the country had, at first, confounded the authorities. Disasters such as the Wenzhou train wreck in 2011 were robustly reported by witnesses, whose posts often defied government censors. But in the past year or so, the screws have tightened. The Cyberspace Administration of China, a powerful censorship agency, took yet another step July 3 when it issued new rules to punish websites that publish unverified content, rumors, hearsay, conjecture and fake news. “Unverified” in this context means “unapproved,” and the real significance of the announcement is to warn websites that news is not what’s trending, but what the Communist Party bosses say it is, period.

Both Russia and China seek to tame the wild and free nature of the Internet, sharing a dangerous and illiberal vision that information should be a ward of the state.