Understanding tacit security regimes

More than three decades after the concept of international regimes was introduced, the study of why and how states may choose to cooperate, particularly around security, remains contested. While the field has evolved considerably over that time, there remain significant puzzles in the literature concerning the emergence of different types of security regimes. We aim to address these issues by developing the concept of a tacit security regime (TSR) literature. We define a TSR as an interest-based, limited, and informal mechanism of cooperation between states for the purpose of deconflicting their respective interests over a specific security issue. We illustrate the usefulness of our concept in the two contemporary cases of Russian-Israeli and Russian-Turkish security cooperation over the Syrian crisis (2015–2018).