Conventional perspectives on multiparty policymaking almost exclusively focus on intra-coalition dynamics within legislative institutions and outline how legislative amendments serve as a tool for policing the coalition compromise and for substantive issue differentiation from governing partners. Only recently, research has begun to examine the role of opposition parties in legislative review. Scholars have demonstrated that while coalition partners are bound by informal rules which limit them to adding to or redrafting government policy (constructive review), opposition parties predominantly engage in bill obstruction and reducing the scope of bills by vetoing individual passages (destructive review).

This article builds upon this finding and examines variation in the substance of opposition legislative review. Specifically, we argue that issue ownership explains opposition parties' choice between collaboration and obstruction of government bills. The paper argues that opposition parties will turn from destructive to constructive review in their prime issue areas in order to signal substantive engagement in those policy fields that are salient to their voter base. We evaluate this argument using an original dataset of legislative proceedings from two European parliamentary democracies. We rely on automated text analysis to distinguish between constructive and destructive review and adapt conventional measures of text similarity that shed light on the substance of legislative bargaining. The results hold important implications for opposition strategies in multiparty policymaking and the study of legislative review.