Summary

Biological weapons (BW) have been a fixture of warfare throughout history, although states did not have the capability of manufacturing BW arsenals until the 20th century. Few states had strategic objectives for BW production, but the fear of being outmatched by rivals produced arms races beginning in the 1920s. Both hegemonic and rogue states sought BW arsenals, although only Imperial Japan is known to have employed them. International agreements prohibiting BW have been ineffective, but normative, technical, and deterrent constraints have prevented the arms from being used.

BW remain undertheorized in the international studies literature and have not been part of the great debates within the field. The literature on BW has instead been far more technical than that for other categories of armaments. The main division among BW researchers is whether the select agents are likely to be spread by proliferation to rogue states, terrorists, or lone actors or whether the technical difficulties inherent in production mean that only states that have invested in advanced research will be able to harness them.

The biological weapons of the 21st century will be new technologies developed by great power militaries ranging from enhanced supersoldiers to genetic attacks that cause organ failure at the push of a button. These advancements raise difficult questions about Just War, military service, and domestic civil liberties. Just as the advent of nuclear weapons and drones preceded informed debate, military uses of biotechnology have already begun and require examination before they are deployed widely.