I am grateful to Frank Stengel for his critical engagement with my book. To some extent, differences in terminology seem to cloud agreement over substance: whether parties’ differences are traced back to “conflicting ideological commitments” (my words) or “because they lack a common view on reality” (Stengel), I agree with Stengel that members of the German greens and Die Linke “consider military deployments ineffective at best and counterproductive at worst.” Because MPs from these parties often refer to the West’s interventionism as the root cause of the conflict, I follow Brian Rathbun and use Robert Jervis’s term “spiral model thinking” to capture this. My book shows that this argument is barely used on the right end of the political spectrum but frequently on the Left in Germany, Canada, and the United Kingdom.

Stengel’s point that social reality does not act on decision makers in a quasi-mechanical fashion is also easy to endorse. Indeed, the reason I find the study of the party politics of foreign policy so intriguing and rewarding is because the appropriate response to any external event is not obvious, but is politically contested: it is subject to different interpretations, which in turn reflect different core values. When it comes to an explanation of actual foreign policy behavior, however, I caution against attributing all explanatory power to the worldviews of the political parties in government. In the conclusion of my book, I argue that actual state behavior “results from a multitude of factors, including those beyond the water’s edge, such as a state’s position in the international system, its capabilities, and the threats to which it is exposed” (p. 142). This is also because party positions themselves “emerge and evolve in response to external events and as a result of government participation” (p. 142).

Poststructuralists might put the terms “threats” or “external events” into quotation marks to emphasize that these are social constructions, or they might prefer to not speak of them at all because reality itself is simply “unintelligible” (Stengel, p. 10). I agree that processes of social construction are important to study because they mediate the impact of external events in important ways. Limiting one’s analysis to such discourses exclusively, however, suggests—deceptively in my view—that political parties have full discretion in interpreting world politics and acting on these interpretations. If that would be the case, we would witness many more and much more radical policy shifts as a result of changes in government. However, we do not, which points to a reality outside discourse that can exercise considerable pressure on some social constructions to change.

The development of the German greens may serve as an illustration: once in government (1998–2005), their traditional antimilitarism became less pronounced. Although a pacifist wing within the party remained vocal, the parliamentary faction voted in favor of the Kosovo campaign (and later of the intervention in Afghanistan). Whereas in opposition it might have been possible to claim that a peaceful resolution of the Kosovo conflict was possible (if only a competent government was in place), this interpretation of the social reality became more difficult to uphold once a party was in government and thus co-responsible for the diplomatic efforts to manage the conflict. A full account of episodes like these requires both an acknowledgment of real-world events like armed conflicts or terrorist attacks and an understanding of their (path-dependent) interpretations by decision makers, political parties, and the public more broadly.