Garrett M. Graff (@vermontgmg) is former editor of Politico Magazine and the author of The Threat Matrix: The FBI At War. He can be reached at [email protected]

A day after Omar Mateen killed 49 and wounded 53 in an Orlando nightclub, purportedly under the banner of the Islamic State or other terrorist groups, the FBI announced that it had repeatedly scrutinized the shooter in recent years. As shocking as that news might have appeared, it fits a disturbing pattern: Many of the so-called “lone wolves” who have carried out terror attacks in the United States have been previously known by the FBI. Among others, the FBI had investigated Tamerlan Tsarnaev years before the Boston Marathon bombings, Nidal Hasan before he opened fire at Fort Hood and Carlos Bledsoe before he opened fire on a Little Rock military recruiting station in 2009.

Particularly in the wake of the Edward Snowden scandals, we tend to think of the FBI and the sprawling homeland security apparatus as a giant surveillance machine—an all-seeing government eye reading emails, tapping phones, tracking purchases and sitting in vans outside homes as undercover agents infiltrate terror cells. But the circumstances behind the Orlando shooting, counterterrorism experts say, underscore the very different reality: The FBI actually isn’t big enough to tackle the new era of online radicalization and independent-acting lone wolves. It’s not that the FBI didn’t recognize Mateen as a threat; it’s that there are too many people like Mateen and Tsarnaev and Hasan across America today for the FBI to track them all—leaving the vast majority of people who the FBI suspects might harbor terrorist aspirations to go about their daily lives without any regular government surveillance. Experts say it’s a big problem—one that’s been brewing for more than two years as the Bureau has struggled to keep up with a wave of aspirational homegrown jihadists, who act faster and leave fewer clues than would-be terrorists a decade or two ago.


And the resource crunch—as well as the obvious risk of being wrong about leaving someone like Mateen on the streets—has been pushing the Bureau to expand use of its controversial undercover terror stings, which help speed up the road to radicalization, but which also raise deep concerns among civil liberty advocates that the FBI is engaging in entrapment.

The Bureau has repeatedly said over the last six months that it has had more than 1,000 active probes related to the Islamic State. But, of these 1,000 or so suspected terrorists, the FBI only has the resources to thoroughly monitor a select few. The precise number of round-the-clock FBI surveillance teams is classified—and additional teams can be readied in an emergency—but sources familiar with Bureau resources say that the number is “shockingly” low, only in the dozens. At one point last year, sources reported that the Bureau was watching 48 people intensely, a number that is towards the upper limit of the FBI’s regular surveillance resources.

That means that even of the 1,000 American citizens and residents that the government believes are most at-risk of executing a terror attacks—the top .0003 percent most radical threats among the nation’s 330,000,000 residents—only around 5 to 10 percent are under 24-hour watch. The other 90 to 95 percent might face varying levels of surveillance, including periodic physical checks, wiretaps or email monitoring, but it’s far from a foolproof security blanket, as at least one case in the last year violently illustrated.

Monitoring just the FBI’s so-called “terrorist watch list,” another list of known or suspected terrorist or their associates, or “No Fly List” outstrips the government’s surveillance capabilities day-to-day. Somewhere around 300 to 500 U.S. permanent residents and citizens are on the FBI’s watch list, known technically as the Terrorist Screening Database (TSDB). There are approximately 16,000 people on the U.S. government’s “No Fly List,” and while the vast majority are foreigners, even watching only the “fewer than 500 U.S. persons” on that list would far surpass the FBI’s ability to surveil suspects for an extended period of time.

During a telephone conference call a year ago with local and state law enforcement leaders, FBI Director James Comey acknowledged that his resources were stretched thin and asked police chiefs around the country for help with surveillance. ABC News at the time reported “a ‘panic’ and ‘crisis’ inside the FBI because the agency and the rest of the nation’s homeland security infrastructure are not built to deal with the non-stop flow of homegrown extremists and possible threats that mark the current environment within the U.S.”

It’s a problem that’s not unique to the United States: European police and intelligence have found themselves swamped by the sheer scale of ISIL’s potential recruits. In the wake of the Paris attack and police raids across Brussels, one investigator complained about the hundreds of suspects police were supposed to be tracking: “There has been a lot of criticism of us,” the investigator said. “But we don’t have big budgets. We are just a small service. We are overwhelmed.” A U.S. observer, after meeting with Belgium police, echoed that sentiment: “The numbers [of suspects] are simply overwhelming.” Other European countries face the same problem. As CNN reported last year, “Surveillance files have been opened on more than 5,000 suspected Islamic extremists in France, but security services only have the manpower and resources to monitor a small fraction of these numbers.”

A year after Comey’s conference call with U.S. police leaders, the situation remains dire. Even as the Orlando shooting underscores the danger of the would-be jihadist, the Bureau faces a daily resource crunch: Intensive, round-the-clock surveillance is simply too demanding to sustain on a given suspect for extended time periods. Thorough coverage of a single individual requires as many as 30 to 40 agents, technicians and analysts. “That’s not just people—that’s dollars, that’s man hours, that’s technology. You’re potentially tracking their cars, their phones, their computers,” explains one senior intelligence official. “It’s not just the people following around town, there’s a whole infrastructure behind them.”

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Compared to its sprawling national mission—which encompasses everything from investigating bank robberies and white collar crime to gang task forces, drug cases, organized crime, public corruption, and counterterrorism, all spread across 56 field offices and 400 smaller resident agencies—the FBI is actually a relatively small agency. Its agent corps of around 13,000 is roughly equivalent to the size of the Chicago Police Department and about 40 percent of the size of the NYPD. Despite the billions poured into counterterrorism, the agent corps is only about 20 percent larger than it was before 9/11, and those ranks have been worn down: Washington’s budget squabbles and sequestration led in recent years to a lengthy hiring freeze.

The FBI’s size and its budget have obviously had a big effect on the way the organization has gone about fighting the war on terror. Manpower pressures, for example, encourage agents and Joint Terrorism Task Forces to make quick decisions regarding whether a suspect poses a threat. In many of the thousands of counterterrorism cases the FBI investigates a year, what determines who is merely “aspirational” and who might someday be “operational” is often just an agent’s or squad’s intuition. “It’s a tough call each time. Some of these people seem on the surface to be losers going nowhere, but the radicalization timeline has sped up,” a senior intelligence official says. A decade ago, would-be jihadists usually traveled overseas for training—to Pakistan, Afghanistan or Yemen—leaving breadcrumbs for investigators along the way, but now Islamic State propaganda often encourages would-be terrorists to take action at home almost immediately, leaving little time for authorities to notice attack planning. One of the Paris attackers last November, Hasna Ait Boulahcen, a cousin of the plot’s commander, Abdelhamid Abaaoud, had been only radicalized weeks before the attack.

As new information continues to come out, it’s clear that the FBI actually devoted rather significant resources to investigating Omar Mateen. In extensive remarks this week, Comey traced years of contacts between the FBI and Mateen, including the use of an undercover informant, wiretaps and background investigations into his financial history.

Beginning in May 2013, the FBI investigated Mateen following reports of inflammatory comments to co-workers supporting al Qaeda. He was interviewed twice by agents. “He admitted making the statements that his coworkers reported, but explained that he did it in anger, because he thought his coworkers were discriminating against him and teasing him because he was Muslim,” Comey said. “After ten months of investigation, we closed the [case].” A year later, the shooter’s name surfaced in the investigation of a Florida man who carried out a suicide bombing in Syria for a terror group aligned against the Islamic State. “Our investigation turned up no ties of any consequence between the two of them,” Comey said this week. “We’re also going to look hard at our own work to see whether there is something we should have done differently. So far, the honest answer is: I don’t think so. I don’t see anything in reviewing our own work that our agents should have done differently.”

While many pundits are reading the FBI’s decision not to surveil Mateen as a failure to recognize a possible threat, the resource problem reframes that decision subtly: The FBI agents investigating Mateen might well have considered him a possible threat, but still decided that amid finite resources and the limited “derogatory information” on Mateen—known as “derog” in the intelligence community—he wasn’t among the greatest threats.

That decision—to forgo tracking Mateen in favor of pursuing more troubling or more pressing suspects—is hardly atypical. While many tips are quickly dismissed as unfounded, the FBI still investigates—and has contact with—thousands of citizens and residents a year who might be somewhere on the spectrum leading towards radicalization. Figuring out who is likely to pursue violence and who just wants to spout off is an inexact science. Increasingly, given the homegrown threat, many suspects haven’t committed a crime until they launch an attack, leaving the FBI and police agencies little beyond a “spidey sense” to know who to scrutinize more closely. Radical political beliefs, after all, aren’t illegal themselves—nor is railing against the United States or even privately expressing support for groups like ISIL or al-Shabaab. And, as has been repeatedly made clear in political rhetoric over recent days, even purchasing weapons like an assault weapon with high-capacity magazines is legal, no matter what someone’s status is on an FBI watch list. Suspects on the watch list have purchased guns at least 2,265 times since 2004—the very vast majority of which were never used to commit a terrorist act or crime.

“Most people who are involved in this stop at the rhetoric. They’ll make bold claims, they’ll make statements in support of jihad,” the intelligence official explains. “There are a whole series of judgment calls that go along with making those determinations. At the end of the day: ‘Is this the right person to be putting forward our resources on?’”

Sometimes the FBI’s choices about whom to put under 24/7 surveillance have been vindicated: Almost exactly a year ago, Boston police and FBI counterterrorism agents shot and killed 26-year-old Usaamah Rahim outside a local CVS pharmacy after he menaced them with a knife. Rahim had, according to the FBI, been plotting to behead controversial Texas anti-Islam activist Pamela Geller, before reportedly telling associates on a cell phone call that he was going to switch to an easier target closer to home: “I’m just going to, ah, go after them, those boys in blue,” Rahim said, according to a call transcript. “’Cause, ah, it’s the easiest target and, ah, the most common is the easiest for me.” Rahim had been under heavy surveillance for some time, but the call encouraged the Joint Terrorism Task Force to approach him for questioning—which is when he pulled the knife, leading to the fatal gunfire. “This was an investigation that was ongoing. It required 24-7 surveillance of the individual in question,” Boston Police Commissioner William Evans said at the time. “We thought the threat was severe enough that we had to approach him.”

Yet Rahim’s original target—Pamela Geller—also illustrates the limits of the FBI’s current surveillance regime: A month before the Boston incident last year, two gunman had attacked a Texas show, organized by Geller, of cartoon depictions of the Prophet Muhammad; both were killed by police. One of the men, Elton Simpson, had been previously convicted of lying to federal agents after he tried to make plans to travel to Somalia, and he’d been on the FBI’s radar since, but not under total surveillance. Investigators had been regularly monitoring his social media postings and noticed references to Geller’s event and that Simpson hadn’t been spotted for a few days, which helped them issue an urgent bulletin to the event’s organizers just three hours before the attack, a bulletin that didn’t arrive in time. In the wake of the shooting incident, officials defended their lack of focus on Simpson. “There are so many like him that you have to prioritize your investigations,” a law enforcement official said at the time.

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The need to marshal and deploy scarce resources in the face of a growing threat is also one key reason the FBI has dramatically increased its use of informant-aided terrorism stings over recent years. The New York Times reported last week that stings, in which an undercover FBI agent will coax a suspected violent terrorist into committing a prosecutable crime, are now used in “about two of every three prosecutions involving people suspected of supporting the Islamic State.” While critics often complain that the stings are, in effect, “manufacturing terrorism” and often teeter on the edge of entrapment, such cases have proven fast to execute and amassed a successful prosecution track record in court. The Bureau’s view, anathema to many civil libertarians, is that it’s a better use of resources to spend weeks accelerating a radical’s path to violence than to follow him for months waiting for him to do something on his own timeline.

FBI officials also say privately that the stings represent the surest route of ensuring that someone who might be on a path to radicalization doesn’t end up executing a terrorist attack. Many of the individuals swept up in such cases may appear like marginal loners, unlikely to be the next terrorist mastermind, but the nature of today’s threat leaves much ambiguity.

While undercover operations have been used repeatedly in the United States since September 11, 2001, the tactic came into widespread use early in the Obama administration. Many officials point to the case of Carlos Bledsoe, who shot up a Little Rock military recruiting office on June 1, 2009, killing one solider and wounding another, as rewriting the FBI’s terrorism rulebook. It was then that the Bureau moved to combat a new era of “lone wolf” attacks, driven by solo jihadists who were radicalized and encouraged to act through online postings and propaganda, rather than guided by terrorist masterminds overseas after successfully completing training in explosives or small arms. By that fall, FBI agents in Dallas and in Springfield, Illinois, had used separate undercover stings to arrest two men who intended to blow up major buildings. Agents waited until the would-be terrorists had parked the vehicles loaded with informant-provided inert explosives and walked away to escape the detonation, and then made the arrest. The cases were considered a watershed—so much so that the fake pickup truck bomb used by the FBI was put on display at the Hoover Building in Washington.

In the years since, scores of individuals have been escorted down the path to a planned attack by FBI undercover informants, and the practice has attracted increasing scrutiny from critics and civil liberty groups. In 2012, David Shipler wrote in the New York Times, “This is legal, but is it legitimate? Without the F.B.I., would the culprits commit violence on their own? Is cultivating potential terrorists the best use of the manpower designed to find the real ones? Judging by their official answers, the F.B.I. and the Justice Department are sure of themselves—too sure, perhaps.”

Two years ago, former FBI Director Robert Mueller faced tough questions at the Aspen Security Forum about the stings and charges of entrapment. “We know at the outset that anytime we do this that the defense is going to be entrapment and there has to be substantial predication to get over that hurdle,” he told the audience of security experts. “It’s been the defense in probably dozens of terrorism cases that have been tried since September 11. And I challenge you to find one of those cases in which the defendant has been acquitted asserting that defense. I don’t believe there is one out there.”

As the FBI has perfected its techniques—and as the surge of would-be jihadists has continued to stretch Bureau resources—the lengthy investigations and intensive operations of those early stings, though, have shifted to much simpler stings and faster arrests, a reflection, counterterrorism officials say, of how the “radicalization timeline” has sped up. Stings aren’t foolproof; they surely have led some people down a violent road they might have always otherwise ignored, turning “aspirational” terrorists into “operational” ones. It’s not necessarily the best technique, FBI officials will concede, but—lacking the resources to spend months or years following hundreds of potential terrorists across the country—it’s the one most likely to ensure that people like Omar Mateen aren’t still walking around the streets.

As one FBI official explained defensively back in 2010, as the stings were just beginning to raise questions, “If you write them off, they’ll surprise you. At some point, these guys will all default to their lowest ability, and even that can be dangerous. You may not be able to shoot down an airliner with a Stinger, but you can still shoot up a shopping mall.”

Or, as the case might be, an Orlando nightclub.