Do biological weapons still pose a significant threat in today’s world? The COVID-19 pandemic has reignited concerns about biological weapons, with some experts speculating that bad actors—both state and non-state—may be renewing their focus on these tools of destruction. A recent War on the Rocks article by Joseph Buccina, Dylan George, and Andy Weber highlights how advancements in biotechnology, combined with the perceived inadequacies of the U.S. response to COVID-19, could make biological weapons more appealing to adversaries. The authors suggest that China and Russia might deploy biological agents in a “low-boil” fashion to undermine the United States as part of a “Shadow War,” a concept popularized by Jim Sciutto to describe non-linear, hybrid warfare tactics.
While mass-casualty biological attacks by nations or terrorists are unlikely, the threat of biological weapons has not disappeared. That said, this threat is currently at one of its lowest levels since the Cold War. Biological weapons today are primarily tools of assassination, sabotage, and special operations, used to secure regimes or disrupt key targets. For U.S. policymakers, the priority should be to bolster diplomatic and intelligence efforts to address this persistent—but manageable—risk.
During the Cold War, several nations developed biological weapons, but these programs were often short-lived. W. Seth Carus, a leading scholar on the topic, documented 15 national biological weapons programs active between 1915 and the end of the Cold War. By the time of the 1975 Biological Weapons Convention (BWC), the development and use of biological weapons had become highly stigmatized.
After the Cold War, most countries abandoned large-scale biological weapons programs, focusing instead on small-scale efforts geared toward assassinations and sabotage. Even today, the United States assesses that only one country—North Korea—maintains an offensive biological weapons program, while three others (China, Iran, and Russia) engage in activities that raise concerns about compliance with the BWC.
Large-scale military use of biological weapons has become obsolete in the face of today’s advanced conventional weaponry. Historically, most countries that developed biological weapons viewed them as deterrents rather than offensive tools, with a few exceptions like Imperial Japan’s use of plague agents during World War II. Small-scale uses by resistance groups and individuals during this period further underscore how biological weapons were often tools of last resort.
Detecting biological weapons programs remains a significant challenge for intelligence agencies, as early-stage development and production are often small-scale and can be hidden within legitimate civilian research. The failures of Western intelligence to identify the Soviet Union’s extensive program or medium-size efforts in Iraq highlight the inherent difficulty of this task.
In the context of great-power competition, biological weapons have limited but significant roles in covert operations. These include targeted assassinations and sabotage missions carried out by intelligence agencies or special forces. Such operations typically aim to neutralize political dissidents, journalists, defectors, or critical infrastructure without overtly revealing the perpetrator’s identity.
For example, during the Cold War, fears of Soviet biological sabotage against U.S. infrastructure were widespread. Today, similar concerns persist, with countries potentially targeting leadership, command centers, naval ports, and military bases during the prelude to conflict. This “subliminal” use of biological weapons, as David Kilcullen describes it, is less about mass casualties and more about precision strikes that destabilize or degrade an opponent’s capabilities.
The difficulty of attributing biological attacks adds to their appeal in “Shadow War” scenarios. The prolonged Amerithrax investigation and ongoing debates about COVID-19’s origins underscore how challenging it is to definitively identify perpetrators. These attribution difficulties make small-scale, covert biological programs particularly attractive to states seeking plausible deniability.
While the fear of biological terrorism remains, the threat has diminished since its peak in the early 2000s. Aum Shinrikyo’s failed attempts to spread botulinum toxin and anthrax in Japan, coupled with the 2001 anthrax letter attacks, heightened global awareness of bioterrorism. However, large-scale biological attacks by terrorists have not materialized since then.
Groups like al-Qaeda and the Islamic State have shown interest in biological weapons, but operational and logistical challenges have prevented them from achieving significant capability. The U.S. invasion of Afghanistan in 2001 effectively dismantled al-Qaeda’s biological weapons efforts, and the Islamic State’s focus on chemical agents never extended to biological weapons. Lone actors and domestic extremists have experimented with toxins like ricin, but these attempts have been rudimentary and largely unsuccessful.
Advances in synthetic biology and genetic engineering, such as CRISPR, have raised concerns about the potential misuse of biotechnology. However, as noted in a 2018 National Academies of Science report, large-scale production and deployment of biological agents remain highly challenging, making targeted attacks more feasible than mass-casualty events.
The era of large-scale biological weapons use is likely over. Instead, biological weapons are increasingly tools for targeted assassinations, sabotage, and covert operations. These threats, while real, are more insidious and harder to detect or defend against.
In the broader context of great-power competition, the use of biological weapons may also extend to indirect tactics, such as targeting allies or proxies. The weak international response to recent chemical weapons use in Syria and high-profile assassinations using agents like Novichok may embolden future biological weapons use.
To address these evolving threats, policymakers must prioritize intelligence, diplomacy, and collaboration with international partners. While public health investments remain essential, they should not be driven by exaggerated fears of biological weapons. Instead, a nuanced approach recognizing the limited but persistent threat of biological weapons in the “Shadow War” will be key to protecting national security.
