NATO after the invasion of Ukraine: how the shock changed alliance cohesion

Following Russia’s invasion of Ukraine in 2022, experts predicted a NATO revival. The record on alliance cohesion, however, is mixed. Allies achieved consensus on some issues but not others. While some Alliance politics scholars and NATO experts assert that cohesion improved, new scholarship is needed to explain the nature of and changes in cohesion across NATO’s many issue areas. Leveraging organizational change scholarship, I argue that the extent to which an exogenous shock—here, the invasion of Ukraine—aligns with NATO’s mission can explain differences in cohesion on issue areas across three realms. To test the argument, I employ discourse analysis of high-level NATO documents, leader statements, relevant quotes from allied and NATO officials and public opinion polls (2010–2024). Findings reveal the importance of an alliance’s mission for the reconfiguration of cohesion after shock, and the study offers an alternative means for explaining the ebbs and flow of alliance cohesion.