As senior military officers, we see water stress—the lack of adequate fresh water—as a growing factor in the world’s hotspots and conflict areas, many of vital interest to the United States. Our earlier reports have identified a nexus among climate, water, energy, and U.S. national security. We have previously shown how emerging resource scarcity across this nexus can be a threat multiplier and an accelerant of instability. With escalating global population and the impact of a changing climate, we see the challenges of water stress rising with time. It is in this context that we now seek to provide a better understanding of the mechanisms through which water factors into violence and conflict.