In ordering the largest mass expulsion of Russian diplomats ever, the U.S. and its allies have upped the ante in an East-West spy game that dates to the Cold War and cast light on an unspoken but widespread practice in the cloak-and-dagger world: sending operatives abroad under diplomatic cover.
The tallies offered Monday by senior U.S. officials were striking: Far more than 100 Russian spies are on American soil masquerading as diplomats. The U.S. said it was kicking out 60, so even after they're gone, at least 40 will ostensibly remain, free to roam Washington and other major U.S. cities under the official imprimatur of their nation's foreign ministry.
So if they're truly spies and the United States knows it, why not expel them all?
The answer, experts say, is that espionage, while murky, potentially distasteful and often illegal, is an accepted international practice. All countries spy and most if not all send spies overseas disguised as diplomats — including the U.S.
"Embassies and diplomatic mission for hundreds and hundreds of years have been used to spy in adversaries' lands," said retired Army Col. Christopher Costa, executive director of the International Spy Museum in Washington. He said even when spies are discovered, it's often more fruitful to follow them discreetly than to expel them. "The cat-and-mouse game of counterespionage is about understanding who that officer is in touch with."
There's another reason for the U.S. not to go overboard in kicking out known Russian intelligence operatives posted to diplomatic missions: America is in the game, too.
When one country expels another country's representatives, it's both expected and accepted that the country being punished takes reciprocal steps. In 2016, when the Obama administration expelled 35 Russian diplomats, Moscow quickly booted 35 Americans. A similar tit-for-tat played out this month after Britain ousted 23 Russians and the Kremlin ordered out 23 Brits.
That means that the more Russian spies the U.S. kicks out, the more of its own spies are likely to be forced out of Russia, Costa said.
When one country posts spies to its embassy in a friendly nation, it usually "declares" them — telling the host country who they are. Those spies, while publicly still claiming to be diplomats, then act as liaisons to the host country's intelligence services, creating a useful backchannel.
With countries that have hostile relations, like the U.S. and Russia, the governments don't tell each other who the spies are. So a high-stakes game of spy-hunting inevitably takes place.
Every new Russian diplomat assigned to a mission in the United States, like the embassy in Washington, or the Seattle consulate that the U.S. has ordered closed, is assessed by the FBI and other U.S. counterintelligence officials, said John Schindler, a former counterintelligence official and National Security Agency analyst.
Some can be quickly identified based on where they've worked previously and in what positions — historical information that's far easier to track in the modern age of Google, LinkedIn and LexisNexis. Certain positions in embassies are notorious for being filled by spies, such as security officials, political officers and communications specialists, who often are secretly engaged in technical collection of what's known as signals intelligence: intercepting phone calls or electronic communications.
"If you still can't tell, you wait until they get to this country, and you watch what they do," Schindler said. "Are they having clandestine meetings with people? Are they using techniques to avoid surveillance?"
The U.S. has long claimed that as a rule, it does not use certain jobs as cover for intelligence operatives, such as U.S. Agency for International Development workers and Peace Corps volunteers. The theory is that any perception that those staffers might be spies would create serious safety risks for actual humanitarian workers.
Said Schindler: "There are gentleman's rules about this, and there have been for a long time."
During the Cold War, capitals around the globe developed reputations for being awash in thousands of agents working for rival intelligence agencies under diplomatic cover. From Asia to the Middle East and throughout Europe, the East-West tug-of-war played out between spies in cities such as Athens, Bangkok, Beirut, Belgrade, Berlin, Cairo, Tehran and Vienna, often in open sight before unsuspecting passers-by.
After the fall of the Soviet Union, such activity subsided, but it never altogether disappeared. Now it's back with a vengeance.
"The rates of espionage are now as high if not higher than they were in the Cold War," said Angela Stent, a professor at Georgetown University's School of Foreign Service and a former Russia expert on the government's National Intelligence Council. "There is a huge degree of mutual suspicion between the intelligence services that never went away."
In fact, it was only last year that Russia complained bitterly to the United States about American diplomats posted to Moscow and other cities that Russia claimed were really there to spy.
"There are too many employees of the CIA and the Pentagon's espionage unit working under the roof of the American diplomatic mission whose activity does not correspond at all with their status," said Russian Foreign Ministry spokeswoman Maria Zakharova.