The US military has tremendous leverage in many aspects of the US and global economies. What might happen if, over the next few decades, the US Department of Defense (DoD) were to develop and apply synthetic biology methods at scale for applications such as acquiring and sustaining propellants, purified water, food, lubricants, coatings, plastics, clothing, medical supplies, and technologies for waste management and environmental remediation? The resulting investment in synbio would be far-reaching. The DoD’s strategic preoccupation with national security shapes and will to shape applications of engineering biology. Changes in scientific knowledge, public perceptions of risk, international affairs, and domestic politics will define the ethical dimensions of synbio in unique geographical settings worldwide. It will likely be immensely difficult to nudge the DoD toward integrating critical ethical perspectives into synbio R&D management and innovation ecosystems. Nevertheless, making DoD into a testbed where flexible ecosystems are desired and taken seriously is a worthy task for the next generation of synbio leaders.