This paper (co-authored with Thomas Wynter) investigates the emotional impact on citizens of international security threats, with an emphasis on the difference between territorial threats and non-territorial threats. It uses an online survey experiment and borrows tools for measuring emotional states from the psychology literature. Territory is associated with the power capabilities of states, the power of individuals within states to survive and prosper, and with one of the most fundamental types of identity, ethnicity and nation. Territoriality is exhibited by many animal species, indicating deeper historical or evolutionary roots, even into human pre-history. Despite the fact that international disputes involving territorial issues are much more likely to escalate to violent interstate conflict than those involving other issues (e.g., Huth 1996), there has been little study of the emotional impact of territorial threats on citizens. In this study we investigate emotional responses to the suggestion of territorial threat in a priming experiment. Australian participants were randomly assigned to: (1) Threat condition (no images); (2) Threat condition (with images); (3) Territorial threat condition (no images); (4) Territorial threat condition (with images); or (5) Control. Following the treatment, participants will complete a standard emotional assessment battery (PANAS), from which treatment-group differences are statistically assessed.