NATO’s post–Cold War mission to effect democratisation in target countries by the end of the 2000s encountered a new reality of illiberal challenges to the spirit behind enlargement, strategic partnerships and the counterinsurgency in Afghanistan. Realist IR theory is best fit for an explanation of retrenchment in democratisation as a foreign policy strategy – not as an anomaly but as a natural phenomenon in a world characterised by countervailing forces, power balancing, and uncertainty about the outcomes of political reform. Explaining change in alliance policy requires special attention to the international system as functionally differentiated through hegemony.