When, if ever, should editors not publish a story they think is true, but they know is controversial? Well, if publication is dangerous or useless. That question was suggested by this month’s cover story by contributing writer Mark Williams (see “The Knowledge”).

Williams (for the record, my brother) spent 14 months investigating genetically engineered biological weapons. He immersed himself in their arcane biology, and he interviewed numerous scientists and security experts. But his journalistic coup was securing the candor of Serguei Popov, a former Soviet bioweaponeer.

Popov described how Biopreparat, the Soviet agency that secretly developed bioweapons during the Cold War, created recombinant pathogens that produced novel symptoms. Some of those symptoms were very horrible. In one case, Popov and his researchers spliced mammalian DNA that expressed fragments of myelin protein, the insulating layer that sheathes our neurons, into Legionella pneumophila, a bacterium responsible for pneumonia. In Williams’s account, “In test animals…the myelin fragments borne by the recombinant Legionella goaded the animals’ immune systems to read their own natural myelin as pathogenic and to attack it. Brain damage, paralysis, and nearly 100 percent mortality resulted.” But Biopreparat had more expansive ambitions than poisoning populations. The military scientists who ran the agency wanted bioweapons that could alter behavior, and they investigated using pathogens to induce memory loss, depression, or fear.

This information might be of only sinister, nostalgic interest, but for Williams’s thesis. He argues that the advance of biotechnology – in particular, the technology to synthesize ever larger DNA sequences – means that “at least some of what the Soviet bioweaponeers did with difficulty and expense can now be done easily and cheaply. And all of what they accomplished can be duplicated with time and money.” Williams explains how gene-sequencing equipment bought secondhand on eBay, and unregulated biological material delivered in a FedEx package, can be misused. He concludes that terrorists could create simple weapons like Popov’s myelin autoimmunity weapon, and states could engineer the more ambitious recombinant pathogens that Biopreparat contemplated.

All of this is tremendously controversial. Critics within the U.S. defense community dismiss Popov’s accounts of what Biopreparat achieved. Most security experts believe that creating any bioweapon – let alone a recombinant pathogen – is difficult, and “weaponizing” those agents is nearly impossible. And many biologists, whilst not as sanguine about the difficulties, think that a preoccupation with bioweapons is counterproductive for two reasons: first, because funding biodefense research tends to disseminate knowledge of how to develop such weapons; second, because we don’t have a very good idea of how to defend ourselves against them.