1. Soft Targets

On April 12, 1982, Yuri Andropov, the chairman of the K.G.B., ordered foreign-intelligence operatives to carry out “active measures”—aktivniye meropriyatiya—against the reëlection campaign of President Ronald Reagan. Unlike classic espionage, which involves the collection of foreign secrets, active measures aim at influencing events—at undermining a rival power with forgeries, front groups, and countless other techniques honed during the Cold War. The Soviet leadership considered Reagan an implacable militarist. According to extensive notes made by Vasili Mitrokhin, a high-ranking K.G.B. officer and archivist who later defected to Great Britain, Soviet intelligence tried to infiltrate the headquarters of the Republican and Democratic National Committees, popularize the slogan “Reagan Means War!,” and discredit the President as a corrupt servant of the military-industrial complex. The effort had no evident effect. Reagan won forty-nine of fifty states.

Active measures were used by both sides throughout the Cold War. In the nineteen-sixties, Soviet intelligence officers spread a rumor that the U.S. government was involved in the assassination of Martin Luther King, Jr. In the eighties, they spread the rumor that American intelligence had “created” the AIDS virus, at Fort Detrick, Maryland. They regularly lent support to leftist parties and insurgencies. The C.I.A., for its part, worked to overthrow regimes in Iran, Cuba, Haiti, Brazil, Chile, and Panama. It used cash payments, propaganda, and sometimes violent measures to sway elections away from leftist parties in Italy, Guatemala, Indonesia, South Vietnam, and Nicaragua. After the collapse of the Soviet Union, in the early nineties, the C.I.A. asked Russia to abandon active measures to spread disinformation that could harm the U.S. Russia promised to do so. But when Sergey Tretyakov, the station chief for Russian intelligence in New York, defected, in 2000, he revealed that Moscow’s active measures had never subsided. “Nothing has changed,” he wrote, in 2008. “Russia is doing everything it can today to embarrass the U.S.”

Vladimir Putin, who is quick to accuse the West of hypocrisy, frequently points to this history. He sees a straight line from the West’s support of the anti-Moscow “color revolutions,” in Georgia, Kyrgyzstan, and Ukraine, which deposed corrupt, Soviet-era leaders, to its endorsement of the uprisings of the Arab Spring. Five years ago, he blamed Secretary of State Hillary Clinton for the anti-Kremlin protests in Moscow’s Bolotnaya Square. “She set the tone for some of our actors in the country and gave the signal,” Putin said. “They heard this and, with the support of the U.S. State Department, began active work.” (No evidence was provided for the accusation.) He considers nongovernmental agencies and civil-society groups like the National Endowment for Democracy, Human Rights Watch, Amnesty International, and the election-monitoring group Golos to be barely disguised instruments of regime change.

The U.S. officials who administer the system that Putin sees as such an existential danger to his own reject his rhetoric as “whataboutism,” a strategy of false moral equivalences. Benjamin Rhodes, a deputy national-security adviser under President Obama, is among those who reject Putin’s logic, but he said, “Putin is not entirely wrong,” adding that, in the past, “we engaged in regime change around the world. There is just enough rope for him to hang us.”*

The 2016 Presidential campaign in the United States was of keen interest to Putin. He loathed Obama, who had applied economic sanctions against Putin’s cronies after the annexation of Crimea and the invasion of eastern Ukraine. (Russian state television derided Obama as “weak,” “uncivilized,” and a “eunuch.”) Clinton, in Putin’s view, was worse—the embodiment of the liberal interventionist strain of U.S. foreign policy, more hawkish than Obama, and an obstacle to ending sanctions and reëstablishing Russian geopolitical influence. At the same time, Putin deftly flattered Trump, who was uncommonly positive in his statements about Putin’s strength and effectiveness as a leader. As early as 2007, Trump declared that Putin was “doing a great job in rebuilding the image of Russia and also rebuilding Russia period.” In 2013, before visiting Moscow for the Miss Universe pageant, Trump wondered, in a tweet, if he would meet Putin, and, “if so, will he become my new best friend?” During the Presidential campaign, Trump delighted in saying that Putin was a superior leader who had turned the Obama Administration into a “laughingstock.”

For those interested in active measures, the digital age presented opportunities far more alluring than anything available in the era of Andropov. The Democratic and Republican National Committees offered what cybersecurity experts call a large “attack surface.” Tied into politics at the highest level, they were nonetheless unprotected by the defenses afforded to sensitive government institutions. John Podesta, the chairman of Hillary Clinton’s campaign and a former chief of staff of Bill Clinton’s, had every reason to be aware of the fragile nature of modern communications. As a senior counsellor in the Obama White House, he was involved in digital policy. Yet even he had not bothered to use the most elementary sort of defense, two-step verification, for his e-mail account.

“The honest answer is that my team and I were over-reliant on the fact that we were pretty careful about what we click on,” Podesta said. In this instance, he received a phishing e-mail, ostensibly from “the Gmail team,” that urged him to “change your password immediately.” An I.T. person who was asked to verify it mistakenly replied that it was “a legitimate e-mail.”

The American political landscape also offered a particularly soft target for dezinformatsiya, false information intended to discredit the official version of events, or the very notion of reliable truth. Americans were more divided along ideological lines than at any point in two decades, according to the Pew Research Center. American trust in the mainstream media had fallen to a historic low. The fractured media environment seemed to spawn conspiracy theories about everything from Barack Obama’s place of birth (supposedly Kenya) to the origins of climate change (a Chinese hoax). Trump, in building his political identity, promoted such theories.

“Free societies are often split because people have their own views, and that’s what former Soviet and current Russian intelligence tries to take advantage of,” Oleg Kalugin, a former K.G.B. general, who has lived in the United States since 1995, said. “The goal is to deepen the splits.” Such a strategy is especially valuable when a country like Russia, which is considerably weaker than it was at the height of the Soviet era, is waging a geopolitical struggle with a stronger entity.

In early January, two weeks before the Inauguration, James Clapper, the director of national intelligence, released a declassified report concluding that Putin had ordered an influence campaign to harm Clinton’s election prospects, fortify Donald Trump’s, and “undermine public faith in the U.S. democratic process.” The declassified report provides more assertion than evidence. Intelligence officers say that this was necessary to protect their information-gathering methods.

Critics of the report have repeatedly noted that intelligence agencies, in the months before the Iraq War, endorsed faulty assessments concerning weapons of mass destruction. But the intelligence community was deeply divided over the actual extent of Iraq’s weapons development; the question of Russia’s responsibility for cyberattacks in the 2016 election has produced no such tumult. Seventeen federal intelligence agencies have agreed that Russia was responsible for the hacking.