Deterring aggression is a constant challenge for both small states and their larger allies and partners. This paper asserts that traditional concepts for small states’ defence and deterrence, such as “deterrence by insurgency” and non-offensive defence, are insufficient, and that instead, small states should be encouraged and supported to build up sufficient military capability that allows them to hold adversaries at greater risk. The paper ends with some policy considerations tailored for small states in Southeast Asia, like the Philippines, facing particular deterrence challenges.