Scholars have identified the important roles personal characteristics — such as religion, gender, and race — play in influencing policymakers' position-taking behavior. One important yet overlooked personal characteristic is generation. This personal characteristic is not only influencing individual policymakers’ position-taking behavior; it is also changing some important political realities across Europe. An illustrative example of these changes is Finland's decision to join NATO. Based on documentary analyses of parliamentary speeches and personal interviews with Finnish officials, this article demonstrates that Russia’s 2022 invasion of Ukraine revealed already established, generation-based cleavages among MPs whose parties had long opposed the prospect of joining NATO. The speeches also reveal a dynamic and evolving orientation to the Baltic states among an emerging political cohort of Finnish MPs, who have been socialized in a fully EU-integrated Finland.