In the interwar years Belgium, a second-rank imperial power, feared new threats to its African colonies, most crucially from communists, revisionist Germany and Italy, and the League of Nations. In response, it expanded pro-empire diplomatic action from Europe to the world; increased administrative inter-imperial coordination in Africa; built up political inter-imperial cooperation in Europe, importantly with another second-rank empire, Portugal; and worked with the Brussels-based Institut colonial international, blurring the divide between (interstate) international and (societal) transnational activities. This bundle of activities reflects an increase and diversification of places and institutions relevant for politics beyond the confines of a particular country—for what may be called world politics; and illustrates how in the 1920s–1930s imperial, international, and transnational political activities increasingly interplayed and indeed blended