An article by Annette Idler and Markus Hochmüller examines the condition of hybrid sovereignties in unstable borderlands characterised by conflict, crime and cross-border mobility as well as the competition and collusion between violent non-state actors and state authorities. While in political practice open borders are often associated with mobility (of people), closed borders are imagined as guarantors of security (of nation states). This dichotomy, however, ignores porosity as a third dimension. The article theorises the link between the porosity of borders and complementary governance constellations and discusses its implications for hybrid sovereignty, illustrated with insights from the Colombian-Venezuelan borderlands.