As with most young Czechs, 31-year-old mathematician Petr Glivicky grew up with stories of the 1968 Soviet invasion of Czechoslovakia.

That event has a central place in Czech national memory and has left the country with a deep-seated mistrust of Russia. To this day, allegations of collaboration with Moscow aren’t taken lightly. But how can the Czech Republic, and other countries, respond to allegations of Russia’s political interference without over-reacting?

Glivicky’s experience offers a cautionary tale.

In 2007, when the United States announced plans to establish a radar base in the Czech Republic as part of a missile-defense shield, Glivicky, then a math student at Prague’s Charles University, joined hundreds of other campaigners against the installation.

“There was a general feeling they didn’t want a foreign military base on Czech territory because of the common experience of the Russian military presence here before 1989,” he remembers.

Opinion polls consistently showed overwhelming opposition to the proposed radar, but once the campaign against the facility began to attract attention, something unexpected happened.

Allegations arose that Russia supported the protesters “almost immediately,” recalls Glivicky, now an assistant professor of mathematics at Charles University. “Some journalists were insisting on it in every commentary that they wrote,” he says. “Without any proof or without any suggestion [of proof], they made really serious accusations.”

The anti-radar activists, he says, tried to laugh off the accusations, but the pressure continued. The group began to receive hate mail, while people who recognized campaigners in the street would stop them and accuse them of being paid by the Russians.

Overstating the extent of Moscow’s meddling in Czech politics makes “the Russians much more formidable, much more of a threat than they really are,” says analyst Mark Galeotti.

Russia denounced the radar, but no evidence ever emerged that it had backed the Czech campaign against the U.S. installation. The missile-defense proposals were eventually scrapped in 2009. But the legacy of the suspicions about Russia’s role in the anti-radar campaign lives on.

Over the years, the Czech Republic’s domestic intelligence service (BIS) has repeatedly warned in their annual reports about Russian espionage.

However, the warnings offer little detail and leave the extent of the threat open to interpretation. The shadowy nature of espionage and disinformation makes suspicions about any covert Russian operation difficult to prove. Jakub Janda and his colleagues at Prague’s European Values think-tank believe that the Russian intelligence services have penetrated multiple Czech institutions to disrupt the country’s ties with the European Union and NATO, and pull the Czech Republic back into Moscow’s orbit. Janda points to extensive disinformation efforts by dozens of so-called “alternative” news sites. These sites share opaque ownership structures, pro-Kremlin, strongly anti-Muslim editorial lines and an affinity for conspiracy theories.

‘‘We are not saying that Russia controls them, but we can prove with empirical examples that they are copy-pasting the positions of Russia,” Janda says.

Others are critical of what they argue are analysts and a national media overstating the extent of Moscow’s meddling. The Czech Republic has an “industry of Russia-fearing media analysis,” asserts Mark Galeotti, a British senior research fellow at the Prague-based Institute of International Relations. “If [we] make the Russians much more formidable, much more of a threat than they really are. And we actually play to Putin’s narrative of being a great power.”

Many Czechs believe, however, that one very large clue about the size of the Kremlin’s operations sits out in the open, right in the heart of the Czech capital: the Russian embassy. Its staff size surpasses that of the U.S. or China. BIS, the Czech intelligence service, estimates that “a large number” of Russian intelligence officers are indeed working at the Russian embassy under diplomatic cover.

Galeotti describes the embassy as a “particular den of spies,” but notes that their focus may not be the Czech Republic. “If they were, that would make this the most heavily surveilled country around.” Rather, Prague, located in the heart of Central Europe, can also serve as “a convenient base” for operations in perhaps Germany or Poland as well, he said.

Worried about retaliatory expulsions of Czech diplomats from Moscow, the Czech government has not yet tried to break up the embassy’s collection of intelligence officers.

“We cannot wage a war on a diplomatic front,” says Andor Sandor, a Czech general who ran the Czech Military Intelligence Services in 2001 and 2002.

Another former intelligence chief takes a less nuanced stance. “There is no reason to underestimate [the] Russian secret service,” says Karel Randak, former head of the Czech Foreign Intelligence Service, which handles Prague’s own disinformation campaigns. “From my point of view, they are one of the best, if not the best, in the world.”

To spread disinformation, Czech “agents of influence” can play a valuable role, he continues. “These can be various advisors, owners of publishing houses, or similar people. And in this respect, the Russians have many options and opportunities here,” Randak says.

Some fear that agents of influence already have the ear of 72-year-old Czech President Milos Zeman. Contrary to the policy of the Czech government, Zeman has condemned sanctions against Russia and likened the conflict in Ukraine to a “bout of flu.” (His office has denied that Zeman differs with the government on Ukraine).

Zeman’s resolutely pro-Russian stance has prompted critics like Janda to warn that he is “Russia’s Trojan horse.” One of the president’s most trusted advisors, Martin Nejedly, is the former head of Lukoil Aviation Czech, a subsidiary of the Russian oil-and-gas behemoth Lukoil. Nejedly helped financed Zeman’s political party, Party of Civic Rights, the locomotive for his 2013 presidential campaign.

Others argue that Zeman’s controversial statements are just a populist attempt to win votes in industrial cities and rural areas by undermining Prague’s élite. He has been described as the Czech Republic’s answer to Donald Trump.

Even while stating that the Russian intelligence agencies are a formidable foe, ex-spymaster Randak shares these concerns. He cautions against overstating Moscow’s threat.

Speaking from his own experience as a target of media suspicion, Glivicky believes that mainstream Czech reporters are more anti-Russian than their western counterparts. “I think a lot of journalists in the Czech Republic are writing counter-propaganda against the Russian propaganda.”

“Nuance had been the biggest victim of the current state of debate,” agrees analyst Galeotti, who says he has been denounced as both a “Kremlin stooge” and a “hawk” for his own writing about Russia.