We study how the electoral success of radical right populist parties (RRPPs) affects mainstream parties' defense policy positions. The success of RRPPs threatens the credibility of established left-wing parties with coalition and international partners due to substantive overlap between their and RRPPs' defense-skeptical position. We argue that left parties adopt more assertive defense positions to distinguish themselves from RRPPs, thus increasing mainstream consensus on defense policy. Examining 27 European countries between the end of the Cold War and Russia's occupation of Crimea (1990–2013), we test this argument based on a regression discontinuity design around electoral thresholds for obtaining parliamentary seats. We find that, in response to RRPP success, left parties adopt more assertive defense policy positions, whereas center-right parties stand their ground. This study yields evidence for an adversarial response to the radical right, often thought to have lost out to accommodation, and for mechanisms other than electoral incentives, in a highly consequential domain.

The United States Constitution requires the government “to provide for the common defense.” As a prime topic featured prominently throughout the legislative blueprint of American society, the “common defense” is conspicuously uncommon in today’s policy scholarship and education. Ironically, the policy discipline largely ignores defense issues despite defense serving as the catalyst for establishing policy studies as an academic field in the 1940s. Through decades of military conflict since and obvious relevance to practitioner behavior, defense issues remain ironically absent the public policy scholarly landscape and are instead hosted primarily within strategic and security studies mediums. This article offers an historical examination of the evolution, development, and scholarly shifts in defense policy over time. It also presents perceived reasons for the lack of defense policy dialogue, recommends approaches to reintegrate the topic back into the scholarly discourse, and concludes arguing defense policy warrants greater attention in academic scholarship and teaching.