In October, 2016, while Russia was meddling in the U.S. Presidential election, it was also accused of another interference operation—this one violent, and targeted at Montenegro. Milo Djukanovic, then the country’s Prime Minister, and the Democratic Party of Socialists were running on a platform to join NATO, whose expansion Russia’s President, Vladimir Putin, famously opposes. In the lead-up to the parliamentary election, Russian state entities directed funds to the parties challenging Djukanovic. “I can tell you with certainty, tens of millions,” Djukanovic said. According to the Montenegrin government, Russia also spread disinformation on social media—including accusations of widespread voter fraud—and launched cyberattacks against government and news Web sites. For the night of the election, Russian agents allegedly had planned a violent coup d’état, which would have culminated in Djukanovic’s assassination and the installment of a pro-Russia government. Montenegrin authorities said that they broke up the operation the night before, and Djukanovic’s party won the election the next day. Last year, Montenegro became the twenty-ninth member of NATO. It is currently applying for membership in the European Union.

I recently sat down with Djukanovic, who is now the President of Montenegro, in a common room at Oxford, following a speech he gave about his country. Djukanovic, who is fifty-six years old and six feet six, has a commanding presence. (The Times once ran an article about President Barack Obama and other athletic heads of state, including Djukanovic and Putin. Djukanovic and Obama both played basketball; Putin, judo.) He spoke calmly for someone describing a violent conspiracy against him, though sometimes he’d talk over his translator in impassioned bursts. He told me that he expects Russia to interfere in his country’s elections again. “It is high time that we organize ourselves to defend and preserve our values,” he said. Like the investigation into Russian interference in the U.S., the investigation in Montenegro is ongoing. The Montenegrin High Court is currently trying fourteen suspects—including two Russians connected to the G.R.U, the Russian military-intelligence service, in absentia. The Kremlin has denied any involvement, and Djukanovic’s opponents have dismissed the allegations as political fiction. But American intelligence agencies believe that Russia sponsored the plot. Last year, Senator John McCain called the scheme the most “disturbing indication of how far Vladimir Putin is willing to go to advance his dark and dangerous view of the world.” When I asked Djukanovic if he was certain that the Russian state was behind the interference operation, he leaned forward and replied, “Undoubtedly.”

The U.S. and Montenegro are just a couple of the roughly two dozen countries in which Russia has interfered, in various ways, since 2004. “It’s important to keep in context that Russia’s 2016 operation was part of a pattern of Russian activities in Europe and elsewhere over the past ten years,” Nadia Schadlow, President Trump’s former deputy national-security adviser for strategy, told me. “The current political climate in the United States, the partisanship, the craziness, tends to ignore this history. Everything is focussed on the current President.” On December 1st, Defense Secretary James Mattis accused Russia of trying to “muck around” in the 2018 midterms, drawing the spotlight back on the U.S. But countries like Montenegro, Latvia, and Estonia—all targeted by Russia in recent years, and all boasting populations of fewer than two million—are especially susceptible to Russian interference. “The smaller we are, the more vulnerable we are,” Djukanovic said.

Electoral interference in the digital age—against any open society—is naturally appealing for Putin. In a 2013 article, Valery Gerasimov, a top Russian general, described a modern strategy of hybrid warfare that would make “broad use of political, economic, informational, humanitarian, and other non-military measures”—in other words, actions that fall within the gray zone between war and peace. Through such actions, Russia can weaken or unseat democratic competitors without declaring war, putting soldiers at risk, or spending much money. A Spanish representative to the E.U told me that Spain has detected “constant attempts by the Russians” to covertly meddle in its politics. Arild Heiestad, a Norwegian brigadier general and a deputy military representative to NATO, said that Russian interference is omnipresent. “If you look around the Baltics,” he said, “it’s their everyday life.” David Cohen, who served as the deputy director of the C.I.A. between 2015 and 2017, said that Russia’s meddling in other countries foreshadowed its operation against America’s 2016 election. “We’ve seen Russian interference in Europe for the past ten years. We saw identical techniques: stolen information, misinformation, all of that, in a variety of countries . . . and one of the things we did not do as well as we should have was sound the alarm,” Cohen told me in his Washington, D.C., office. “We didn’t do a good enough job of better preparing ourselves, of saying, ‘The Russians did that there, so there is no reason to think they’re not going to do the same thing here.’”

Earlier this year, Juan Manuel Santos, then the President of Colombia, gave Enrique Peña Nieto, his counterpart in Mexico, an urgent warning: he had reviewed intelligence suggesting that Russia was planning to interfere in both of their countries’ upcoming national elections. (Both Santos and Peña Nieto were term-limited, and therefore ineligible for reëlection.) “We received a lot of warnings that this was going to happen,” Santos told me over breakfast. “I took tremendous care and gave pertinent orders to investigate . . . and even had some foreign intelligence services help us.” After Colombia’s election—which saw the rise of a right-wing populist—Santos found no concrete evidence of Russian meddling. Nor was he aware of any evidence of interference in Mexico’s election, in which a left-wing, anti-establishment figure rose to power. “Again, the Mexicans could not prove it,” he said. But Santos, whose term ended in August, remains unsettled. He recognizes that Russian meddling could have occurred undetected in both countries, and wonders whether he left Colombia equipped with the tools it needs to defend its sovereignty. “I hope I did,” Santos said. “But I can’t control that, because technology advances so fast. Russia is more interested in maintaining the disorder than anything else . . . Fake news and social media, the way it’s designed, encourages and strengthens polarization.”

Since 2016, Trump has both dismissed the threat of electoral interference and sent mixed signals about America’s commitment to NATO’s Article V provision of collective defense. In July, he questioned why the U.S. should enter into “World War III” to protect Montenegro. “That statement did worry me at that particular moment,” Djukanovic said. Smaller countries lack the resources to push back against Russia—whether economically or in the cyber domain—leaving open the question of how America should respond. Santos, the sole recipient of the Nobel Peace Prize in 2016, emphasized that he would prefer no foreign intervention take place at all. However, he suggested that if Russia continues to interfere in foreign elections, the U.S. should respond in kind. “If you are having—in very weak countries—the interference of a world power that has certain values that I don’t share, I would prefer that the power that does have the values that I share to help neutralize what is happening,” he said, when asked whether America should covertly assist leaders targeted by Moscow.