This article explores the violent geographies of the Vietnam War. It argues that the conflict is crucial for understanding the security logics and spatialities of U.S. state violence in the war on terror. An overarching theme is that U.S. national security has inherited and intensified the atmospheric forms of power deployed across Southeast Asia, including ecological violence, the electronic battlefield, counterinsurgency (the Phoenix Program), and drone surveillance. All of these attempted to pacify and capture hostile circulations of life and place them within the secured and rationalized interiors of the U.S. war machine. The article thus expands on the concept of atmospheric warfare. This is defined as a biopolitical project of enclosure to surveil, secure, and destroy humans and nonhumans within a multidimensional warscape. Since modern state power is becoming ever more atmospheric-particularly with the rise of drone warfare-dissecting the origins of that violence in the Vietnam War is a vital task.