ISIS sympathizers pose a terrifying dilemma for law-enforcement officials, who have to sift through droves of online aliases engaged with propaganda—whose owners might live in America or abroad—to identify people who credibly wish to harm the United States. The accounts may not be accessible because of encryption, the FBI agents working the Mississippi case told me, and leads can go dark. Americans expect their government to prevent violence before it happens: Their shared national nightmare is the plot that goes undiscovered before an attack or the known sympathizer who gets away. Faced with such high stakes and uncertainty, the FBI is left to teeter between catching people before they act and walking along with them until they violate the law.
The most remarkable thing about Jaelyn and Moe is that theirs was a largely straightforward case. In less than three months, the FBI had crafted a powerful indictment against them. Theoretically, when the Bureau comes across two kids like Jaelyn and Moe—lost, in love, and grasping toward a dark future—agents could try to set them on another path, reaching out to their families and communities. In reality, though, that’s not what the country has asked them to do.