The novel coronavirus presents significant challenges to the mission and operations of every government agency and department—and the Central Intelligence Agency is no exception. In fact, the agency’s intelligence officers now face a more difficult challenge than ever when it comes to their efforts to recruit spies.

Normal techniques don’t work under the unique circumstances created by the virus. Bumping up against disaffected foreign diplomats or disgruntled terrorists? Difficult when virtually all public events have been canceled. Developing a relationship of trust with a potential intelligence asset? Far from a cakewalk when lengthy face-to-face meetings are a nonstarter. Conducting surveillance detection before meeting with a recruited asset or gathering material from an asset’s dead drop full of secret material? Good luck avoiding attention from local law enforcement and counterintelligence when the streets are otherwise empty. And don’t even try to pull off a brush pass when social distancing demands at least six feet of physical separation.

But all is not lost. U.S. intelligence has a long and distinguished record of working against oddly similar foes in oppressive environments—most notably, the Soviet Union’s KGB on the streets of Moscow. Pervasive, invisible and potentially lethal, the KGB’s smothering embrace led the CIA’s operations officers to do some of their best work to complete one of their most successful operations.

This legacy of creativity and technological innovation will serve their successors in today’s CIA well. And it must, because COVID-19 presents the most widespread obstacle to human intelligence collection in the agency’s history.

To gather intelligence from human sources, intelligence officers have long used a logical and rigorous process. They must find potential spies, determine what information those targets can provide (and how reliably), develop a relationship of trust, convince them to commit espionage and handle the flow of secret information from those people.

This process—spotting, assessing, developing, recruiting and handling—is known as the recruitment cycle. And each stage works best when intelligence officers can look sources in the eye, earn their trust, calm their anxiety and share their peril. Technical solutions can help in some cases, with one or more of the steps in this process, but they cannot reliably replace the human touch in all of them.

Spotting refers to finding someone who might make a good asset. An intelligence officer can come across this person by chance. More often, however, the officer targets a specific person (or a type of person) who can fill intelligence gaps, on anything from an adversary’s military research and development to a terrorist group’s attack plans to a foreign leader’s political agenda. Put simply, an intelligence officer looks for an individual who can provide secret information that will prove valuable for political and military decision-makers and for the analysts who provide all-source assessments to those decision-makers. Spotting can take place almost anywhere, from the internet to swanky diplomatic receptions, with an emphasis on face-to-face encounters with interesting people.

After an intelligence officer spots a potential asset, she must assess that person. Many questions come into play, among the most important being: Can this individual both provide needed intelligence and remain willing to provide more? During this phase, the intelligence officer gauges what motivates this candidate—money, ideology, ego or something else—and how best to satisfy this motivation in return for something of value to U.S. national security. Spending significant amounts of time chatting with, and listening carefully to, what the potential asset is saying (and also leaving unsaid) informs these judgments best.

Once an intelligence officer better understands a potential asset’s motivations, it’s time to develop and groom that individual, leading them to the point where they are ready to commit espionage. This often involves escalating requests for information. Having would-be spies carry out ever more perilous tasks, talking to them about how they did it, tasking them with what to get next and advising them on covering their tracks can happen quickly, but this process usually takes extensive patience and one-on-one guidance.

Recruitment is the formalization of the relationship that formed during the assessment and development phases. Getting the asset to agree to the clandestine relationship ensures that they know what they are getting into—and commits the handling officer and the agency as whole to giving them something in return (be it cash, the satisfaction of helping the American cause or something in between).

Handling refers to the meticulous work of managing the now-recruited asset. As the word implies, handling often involves direct contact with the asset to ensure that they stay on track, even as intelligence requirements change. This covers everything from tasking the asset to perform certain tasks to keeping them safe while they do so. Constant assessment and development, ideally with face-to-face meetings, helps get the most value out of the asset.

In many ways, the recruitment cycle is like marriage. You spot a potential partner. You assess whether you might work well together. You develop your relationship, learning what each of you can bring to the other and gauging how the other person ticks. If the relationship develops well, the marriage proposal (recruitment) comes as no surprise and is the natural next step. Then, over time, the marriage must be maintained and managed to provide each side with what they need.

Like a marriage, a healthy relationship between an intelligence officer and an asset usually features ample attention and extensive energy—and, of course, a lot of time spent with one another.

Operational acts in service of these steps of the recruitment cycle are designed to blend into normal behavior. As normal behavior in most countries has begun defaulting to staying home, the business of espionage almost certainly has become extraordinarily difficult.

At a minimum, targeting potential intelligence assets in any given city would become difficult if that locale’s government were to ban all parties, trade shows, conferences and other gatherings, as many cities have. Without that first stage in the process, the subsequent stages won’t be happening for quite some time.

But what about assets who have already been spotted, with whom communication has already begun? Assessing, developing, and ultimately recruiting and handling them as intelligence sources almost universally requires physical contact. In a growing number of places, however, face-to-face meetings have become nearly impossible. From Italy to Iran to Spain, streets are largely empty. Anyone out and about could quickly face questions from authorities and well-meaning locals alike.

Even the few quick trips people risk in many parts of the world remain limited largely to shops close to home. In an expanding set of cities, where the bulk of espionage occurs, people can no longer blend into large crowds when going out for a casual jog, exercising in a park or engaging in any related activity that traditionally has provided cover to meet with an intelligence asset or to pick up secreted material. A dead drop might still be possible—but perhaps only for officers with dogs, because walking canine companions is one of the few outdoor activities still allowed in many places.

Massive travel disruptions are likely to stall operations at both ends of the recruitment cycle. Intelligence officers typically travel to convenings around the globe to spot and assess potential targets. Now, those diplomatic parties, business conferences and trade shows are canceled. And travel overseas to meet with fully recruited spies, too, is in jeopardy. Think about the trips that Aldrich Ames made to places like Colombia and Austria to deliver classified material to, and receive payments from, his Soviet handlers. Now, though, borders are closing: Travel is limited between the United States and Canada, and non-Europeans cannot travel to the Schengen Zone. Airlines, trains and other modes of transportation in some countries have all but shut down. Even if an intelligence officer can get a flight to a third country, there’s no guarantee she can make it home.

This is particularly damaging for efforts to collect information from so-called “hard target” countries, those with exceptionally watchful internal security services. To avoid what must seem like the certainty of detection in their own countries, spies often prefer to use trips abroad to meet covertly with their handlers. But now, they may not be able to get out at all. Even worse, how would each asset’s handler know that a particular asset isn’t dead or sick, a victim of the very virus that’s curtailing travel?

Although COVID-19 has made most of the globe unsuitable for traditional intelligence operations, that doesn’t mean all operations will be put on hold. The agency has dealt with situations like this before, sometimes because of localized disease outbreaks but most often due to totalitarian states’ omnipresent surveillance and xenophobia. Doing the business of espionage in such “denied areas,” as CIA officers have called them, requires patience, creativity and technology. But it can be done, as the declassified history of U.S. intelligence operations inside the Soviet Union during the Cold War shows.

The streets of Moscow and other cities within the USSR, decade after decade, proved incredibly hostile for U.S. intelligence due to the watchful eyes and ears of KGB officers and the paranoid political culture. Intelligence officers sent there from Langley or from other overseas stations and bases routinely found the environment more challenging than other assignments.

After the arrest and execution in the 1960s of Oleg Penkovsky, a colonel in Soviet military intelligence who provided the West with valuable information about the USSR’s nuclear capabilities, face-to-face operational meetings in the country stopped. Quickly, however, intelligence leaders realized that trying to spot, assess, develop, recruit and handle spies without the human element left gaps in U.S. policymakers’ understanding of the USSR, which they recognized as the greatest threat to American national security.

So they got creative, using innovative techniques to all but eliminate face-to-face contact—a model for what may need to be done in this coronavirus era.

Good examples come from the CIA operation to handle Soviet diplomat Alexander Ogorodnik, codenamed TRIGON, right under the noses of the KGB in Moscow. While agency officers had met with TRIGON extensively in his previous assignment, they met with him only a single time after he returned to the USSR. And for that meeting, with so much at stake in the oppressive surveillance environment, the CIA designed a new disguise technique called identity transfer—enabling a quick meeting without an obvious intelligence connection.

The operation proceeded using tools and technology from the CIA’s Office of Technical Service, ranging from new dead drop gadgets to an invisible earpiece allowing officers to listen in on the host country’s surveillance communications—which allowed CIA officers to keep their distance. Exquisite intelligence rolled in. TRIGON’s window into the machinations of the Soviet nomenklatura, unavailable in open-source literature, provided insights into the USSR’s intentions and capabilities. More importantly, he eventually gave up the Soviets’ negotiating positions during the SALT I and SALT II arms talks—a landmark prize from a landmark case.

Perhaps CIA Director Gina Haspel had TRIGON in mind when she recently said in a speech, “Within the Intelligence Community, CIA is the keeper of the human intelligence mission. Technical forms of collection are vital, but a good human source is unique and can deliver decisive intelligence on our adversaries’ secrets—even their intent.”

Minimal in-person connections or on-the-street actions remain necessary except in the rarest of circumstances. Even in the TRIGON case, dead drops still had to be made and picked up. Such on-the-street activity could continue in Moscow then because of deception and illusion tools, many straight out of Hollywood: small, inventive dead drops enabling quick transfer of film; identity transfer allowing officers to ditch surveillance momentarily; and much more. Technological advances since the mid-1970s have surely expanded intelligence officers’ toolkits for avoiding face-to-face contact well beyond what was available then. But help from gadgets, disguises and advanced communication methods could matter only at the margins.

During the peak of COVID-19, such operational acts simply cannot carry on as they were before. In many countries, nothing approaching the regular handling of existing assets is likely to proceed in the near term. New cases will prove extraordinarily difficult to get off the ground. Nobody can say with confidence how long virus-related restrictions will continue. If they go on through most of 2020, the impact on CIA operations will be significant.

With all the challenges intelligence officers have faced in recent years, the ominous cumulonimbus of COVID-19 is the last thing they need now. It will take another leap, like that developed for TRIGON a generation ago, to overcome the major obstacles that the social distancing response to the coronavirus has thrust in the way of robust spy-recruiting tradecraft.