Drawing on recent debates in English School (ES) theory, this article develops an analytical framework for examining how states use multilateral institutions, or what ES theorists call ‘secondary institutions’, to reshape ‘primary institutions’, i.e. fundamental practices in international society. The framework highlights the role of states’ agency in international institutional change by shedding light on strategies that they employ to bring about changes in primary institutions. It posits that, although they can seek to directly remould primary institutions, states in practice often seek to bring about primary institutional changes through existing or newly formed secondary institutions and that this is especially the case at the level of regional international societies (RISs). The article demonstrates the utility of the framework by using it to analyse the case of Russia’s peacekeeping policy in the post-Soviet regional international society (PSRIS), focusing on its efforts to institutionalise the Collective Security Treaty Organization (CSTO) as an alternative ‘peacekeeping’ actor.
