The weekend’s stunning repudiation of further European bailouts by a strong majority of Greeks shocked Brussels and beyond. That 61 percent of Greek voters want nothing to do with European Union “fixes” to their country’s grave fiscal crisis, which has preoccupied the EU for five years, represents a shocking development to Eurocrats.

What happens next is on everyone’s mind. Unless Athens comes up with a revised—and more plausible—finance plan very soon, expulsion from the Eurozone appears imminent. While that could cause financial instability for Europe, and may bring bad tidings far beyond, there’s one country that seems to be savoring this crisis.

That’s Russia. To the surprise of no one who pays attention to Vladimir Putin’s persistent efforts to undermine the EU and NATO, Moscow is poised to reap political benefits from Greece’s financial collapse.

The morning after the referendum, Greek Prime Minister Alexis Tsipras spoke with Putin to discuss the fallout—a full day before Tsipras spoke with President Obama.

Neither are close ties between Athens and Moscow anything new, or exactly hidden. Tsipras’s first foreign outreach upon becoming prime minister was to Moscow’s ambassador—not to EU or NATO partners.

The affection of Greece’s ruling Syriza party for much of the Putin worldview, including a reflexive anti-American and anti-NATO posture with strong doses of “anti-imperialist” rhetoric, isn’t something Athens has been shy about. Although Syriza’s far-left political orientation would seem to make it an unlikely partner for Putin’s conservative, even traditionalist, Kremlin, shared anti-Western values seem to be enough.

Syriza’s robust Moscow links exist at several levels and are nothing new. Ideological harmony has been matched by money deals behind the scenes. Long before taking power at the beginning of this year, party leaders had regular discussions with top Russian officials as well as with far-right activists like Alexander Dugin, a neo-fascist ideologue who intermittently has the Kremlin’s ear.

Unsurprisingly, given the extent of Greece’s financial-cum-political crisis, anti-EU and anti-American sentiments run deep, to a degree not found in any other NATO country. Mounting concerns that Athens is falling into Moscow’s orbit, its ostensible Western political and military ties notwithstanding, are no longer a fantasy.

“For Athens, NATO seems to be mostly a paper exercise at this point,” a senior Alliance official told me, expressing a common frustration at Alliance headquarters, where Greek representatives are viewed with mounting suspicion. Many in NATO fear that information shared with Greece, including intelligence, is winding up in Moscow. Recently the Alliance executed a long-overdue cull of Russian liaison officers in Brussels, many of whom were barely concealed spies, and now there’s fear that the Kremlin can make up that setback with Greek help.

It’s premature to suggest that Greece might actually leave NATO, much less the EU, since Athens gets considerable benefits from both partnerships, but it’s certainly time to ask where that country’s sympathies truly lie. More than a shared Orthodox faith, buttressed by hazy paeans to long-dead Byzantium, is at work now in the relationship between Athens and Moscow.

The involvement of Russian intelligence in present-day Greek turmoil plays an important role, albeit one seldom discussed openly. Greece has long been a playground for Kremlin spies. During the Cold War, KGB operatives worked in Greece with a degree of impunity they found in no other NATO country, while Soviet spies penetrated Greek politics and society very deeply.

Under Putin, such covert linkages have been reestablished, and secret Russian activities in Greece today enjoy a degree of openness they never had in Soviet times. Since Syriza came to power, the already significant contingent of Russian intelligence officers serving in Athens under official covers (usually as diplomats) has been bolstered, according to Western security officials. Friendly meetings between Greek officials and representatives of the SVR and GRU, Russian military intelligence, detected by NATO intelligence, have been a cause of discussion and concern in Brussels, Washington, and beyond.

It’s not like Syriza has been hiding all of this. Defense Minister Panos Kammenos, shortly after a visit to Moscow last fall, signed a memorandum of understanding between his Athens think tank, the Institute for Geopolitical Studies, and a Moscow counterpart, the Russian Institute for Strategic Studies, known as RISI.

However, RISI is no ordinary think tank. Headed by Leonid Reshetnikov—a career KGB officer who retired as a lieutenant-general and the head of analysis for the Russian Foreign Intelligence Service, or SVR—RISI is a Kremlin outfit, a sort of governmental NGO that functions as the public face of Putin’s vast intelligence apparatus. Officially RISI is no longer part of the SVR, falling under the presidential administration, but no Western intelligence services accept that claim at face value.

Reshetnikov, a one-time communist but now a devout, indeed militant, Orthodox Christian, is close to Putin and is one of the top movers and shakers in the Kremlin when it comes to spy matters. Speaking Greek and Serbian, he plays a large role in Russian activities in the Balkans, which have increased noticeably in recent months. Reshetnikov’s regular trips to southeastern Europe, where he denounces Western “imperialism” and does photo ops with senior Orthodox clergy, feature in local media, usually with praise.

Prime Minister Tsipras, too, has visited RISI headquarters, leading to the odd situation that one of the top security partnerships possessed by a NATO and EU country is with Putin’s foreign intelligence service. Current government assessments coming out of Athens “read like they’re written by the SVR—which they probably are,” bemoaned a European intelligence official. “We’ve always had our doubts about the Greeks,” he added, “but today’s situation is even worse than it was during the Cold War. The Russians are quietly running the show.”

Rumors of Russian money and influence calling the shots in Athens—or at least playing an outsized role—are no secret in NATO security circles. That Putin wants to harm Greece’s already precarious links with the EU and NATO is plain to see, and it seems to be getting close to fruition as the Greek crisis worsens.

“They’re only technically on our side,” explained a retired CIA officer with long experience in Greek matters. U.S. intelligence has never fully trusted the Greeks, with the CIA especially having misgivings stemming from the 1975 murder of Richard Welch, the agency’s station chief in Athens. While Langley blamed Phil Agee, a former CIA officer who went over to the Cubans and Soviets—think of Agee as the Ed Snowden of the mid-1970s—for Welch’s death, it was long obvious that Athens was never very eager to catch Welch’s killers. Neither did the 1988 terrorist assassination of the U.S. naval attaché to Greece, Captain Bill Nordeen, promote trust.

Ties between U.S. intelligence and the Greek security services suffered for years, and things are getting unpleasant again. “We’re back to square one,” rued the former CIA case officer. “It’s like the bad old days when we didn’t trust the Greeks and they didn’t trust us. Only now Putin’s in the middle of the game.”

Time will tell if Moscow can pull a strategic win out of Greece’s mounting chaos. But there’s little doubt anymore that the Syriza government’s barely concealed ties with the Kremlin, particularly with its intelligence services, are causing serious heartburn inside NATO and the EU alike. It’s now Putin’s game to lose.