The spring and early summer have featured two crises in America: the coronavirus pandemic and the uprisings following the police killing of George Floyd. One thing has bound them together: the difficulty of separating facts from disinformation. A major driver of this has been autocratic regimes — China, Russia and Iran — using social media to try to influence American public opinion. History may provide the key for separating fact from fiction. It reveals how and why a one-party regime used disinformation to salvage its reputation following a disaster. This happened with the Soviet Union’s 1986 Chernobyl nuclear catastrophe, whose history also reveals how such disinformation can be countered.

The HBO series “Chernobyl” showed in chilling detail how Soviet authorities created a cloud of lies after the Soviet nuclear power plant in Ukraine melted down on April 26, 1986. Though brilliantly made, the show did not reveal the extent to which the Soviets tried to manipulate Western media reporting about the tragedy. Once secret Soviet intelligence archives in Ukraine have exposed how Moscow used its secret police and state-run media to manufacture alternative facts about the disaster’s cause and fatalities, which threatened the Soviet regime’s legitimacy.

Immediately after the disaster, Soviet intelligence pursued “active measures” to protect its reputation. Such efforts were orchestrated by a special department in the KGB, “Service A,” which had long used forms of covert political warfare to influence world events in Moscow’s favor. These “dirty tricks” included forgery, disinformation and interfering in foreign elections. According to a high-level KGB defector to the United States, Stanislav Levchenko, in the 1980s, Service A deployed approximately 15,000 personnel.

Following instructions from KGB headquarters, “the Center,” the local Ukrainian KGB undertook active measures to influence western investigative journalists reporting about Chernobyl. In one instance, the KGB stole soil samples that a French journalist had taken from the radiated disaster zone and swapped them for non-contaminated samples. In another, the KGB targeted Newsweek’s Moscow correspondent, Steven Strasser, who reported about Chernobyl.

After Strasser arrived in Kyiv in June 1986, the KGB deployed eight officers and 19 members of a local volunteer brigade to “hinder his actions” and prevent his “collection of slanderous information.” In a recent interview with me, Strasser recalled that these efforts were hardly clandestine — a phalanx of “KGB goons” surrounded him as he tried to interview people on Kyiv’s streets. The KGB’s active measures against Strasser centered on a female agent, code-named “ROTA” (“Squadron”), who reported on his activities. She was probably his official Soviet Intourist (‘foreign tourist’) minder. It was an open secret that Intourist housed KGB officers and agents. After she stepped in, the KGB goons disappeared, leading Strasser to surmise at the time — correctly — that she outranked them.

Soviet authorities were unsuccessful in manipulating Strasser’s journalism about Chernobyl. In a Newsweek article on June 16, 1986, for example, he described Kyiv’s slow response to prevent children playing outside after the reactor meltdown, 80 miles away. However, the Soviet attempts do expose how a paranoid one-party regime labored to protect its reputation from Western investigative journalism following a disaster.

Another Soviet active measure was to forge documents to distract from Soviet mishandling of Chernobyl and deflect criticism to the United States. In Chernobyl’s aftermath, Service A concocted a letter purportedly written by a senior member of the U.S. Information Agency, Herbert Romerstein, a vocal anti-communist, who led America’s efforts to counter Soviet active measures. In the bogus Soviet letter, dated three days after Chernobyl, Romerstein purportedly instructed Sen. David F. Durenberger (R-Minn.), chairman of the Senate Select Committee on Intelligence, about how the United States could “make the Chernobyl disaster into an effective propaganda campaign” against the Soviet Union. The KGB created its fake letter from an authentic one written by Romerstein, sent to a Czechoslovakian diplomat, retaining its original letterhead and his signature but inserting bogus text.

Unknown to the Eastern Bloc diplomat, Romerstein was prepared for potential manipulation and had inserted unique markings on his letter. When the forgery surfaced in the United States in August 1986, anonymously mailed to The Washington Post, it carried Romerstein’s secret markings. He confronted the Czech diplomat, who admitted that he had sent it to Prague, from where it presumably made its way to Service A. The U.S. Information Agency then exposed the forgery in a news conference. Instead of creating news about U.S. disinformation, the Soviet disinformation became the story The Post ran. As Romerstein later recalled, the FBI “used the forgery as an example of KGB methods, and we in fact got more mileage out of it than the Soviets ever could have.”

Despite these tactical failures, KGB efforts were strategically successful. Through a constellation of Soviet front groups in Western countries, it promoted the message that Chernobyl could happen anywhere, even the United States. The disaster was the inevitable result of all nuclear power. KGB messaging was recycled and amplified by Western “useful idiots” — the KGB’s term — in Soviet-front “peace” organizations and groups like the Campaign for Nuclear Disarmament. With KGB help, “Chernobyl” became a byword for the problems of nuclear power generally, not lethal Soviet mismanagement.

Since the end of the Cold War, Russia’s intelligence services have deployed similar tradecraft to protect its reputation and discredit the United States. This is unsurprising given that Russia’s leader, Vladimir Putin, a former KGB officer, graduated from the KGB’s training school, the Andropov Institute, where recruits were instructed in active measures. Modernizing old KGB tradecraft for the digital age, Russian operatives have again created disinformation about disinformation, posting forged documents to discredit U.S. officials like Robert S. Mueller III who investigate Russian hacking and disinformation. As with Chernobyl, Russia’s recent efforts were exposed through careful U.S. intelligence forensic work.

The history of Soviet disinformation in the later Cold War provides lessons for how best to counter similar efforts, whether China’s attempts to salvage its reputation amid the coronavirus pandemic, Russia’s aim to interfere in another U.S. presidential election or efforts by Russia, China and Iran to fan the flames of racial division in the United States.

The most effective disinformation is inflicted by Western societies on themselves, true believers willing to amplify falsehoods. The year before Chernobyl, CIA officials testified before Congress about the nature of Soviet active measures. Robert Gates, future CIA director and defense secretary, explained that exposure was the best strategy to defeat disinformation. When probed by a senator about the actual threat Soviet active measures posed, Gates said they were mostly a nuisance and generally did not pose a strategic threat to the United States. However, Gates warned, “in a close election or legislative battle, they could spell the difference.”

The senator asking questions about Kremlin disinformation was Joe Biden. His presidential campaign today should heed the same principles that he identified then about countering disinformation. Then, as now, light is its best disinfectant.

Today’s social media landscape makes it quicker, easier and cheaper to spread disinformation than the KGB ever could. Unlike the past, today’s White House has also itself learned the power of misinformation, with President Trump regularly tweeting about conspiracy theories and unproven medical treatments and castigating journalists for asking hard-hitting questions. Disinfecting light needs to be cast not only on China’s coronavirus disinformation, but also on America’s own catastrophic virus meltdown.