The Politics of Alliance Cohesion: Experimental Evidence on American Attitudes Toward Corrective Measures in Security Partnerships

Member countries within a security alliance are expected to uphold their alliance obligations. However, in reality, member states may strategically deviate from alliance commitments, potentially undermining the alliance's cohesion and other party’s strategic interests. In such instances, the stronger partner has several options: it can ignore these deviations, particularly if it does not prefer the risk to the vitality of the alliance, or it can adopt corrective measures to reinforce compliance and signal to other members that such misbehaviors will have consequences. These corrective strategies encompass a continuum from rhetorical actions, such as public shaming and blaming, to coercive measures, such as sanctions or suspension of military support. A critical determinant moderating the effectiveness of corrective measures is their perceived credibility, which is intrinsically linked to the domestic political endorsement these measures garner in the sender country. When corrective measures lack popular legitimacy, the targeted state may anticipate and strategically exploit potential audience costs, thereby undermining the intervention's potential efficacy. Conversely, corrective measures with robust public backing in the sender are perceived as more credible by the target and, consequently, carry enhanced diplomatic leverage. Despite its pivotal role, existing scholarship has not systematically examined the public opinion dimension of alliance restraint. Aiming to fill this gap, in this paper, I examine public preferences for corrective policies toward security allies that renege or underperform on their alliance commitments. The research advances three primary hypotheses: First, citizens of the dominant partner will demonstrate a preference for corrective measures against uncooperative allies, with a particular predilection for high-coercion interventions. Second, exposure to information regarding allies' uncooperative behaviors will generate negative alliance perceptions and stimulate demands for reduced national contributions to the alliance. Third, contextual variables will moderate citizens' support for corrective measures, with lower support anticipated for allies with a democratic regime, substantial military capabilities, and sharing a formal alliance treaty with the home country. Empirical analysis based on a pre-registered survey experiment involving a nationally representative sample of over 1,502 American citizens provides substantial evidence for these hypotheses. The findings demonstrate strong public support for corrective measures, particularly coercive strategies such as economic sanctions and military aid reduction, against allies who violate alliance commitments. While alliance violations generally trigger demands for reduced American contributions, public response varies significantly based on the nature of the transgression and the characteristics of the transgressing ally. Notably, the study finds that regime type significantly moderates support for corrective measures, with Americans demonstrating marked reluctance to endorse punitive actions against democratic allies. However, neither the ally's military capabilities nor the presence of formal treaty arrangements significantly moderates public preferences on corrective measures. This study provides the first experimental evidence of American support for wielding pressure and restraining members within a security alliance. As such, it makes a substantive contribution to our understanding of alliance management and the domestic foundations of international cooperation, while offering insights into the constraints and opportunities leaders face when addressing alliance non-compliance.