Previous research suggests that political parties learn from and emulate the successful election strategies of governing parties in other countries. But what explains variation in the degree of influence that governing parties have on their foreign counterparts? We argue that clarity of responsibility within government, or the concentration of executive responsibility in the hands of a dominant governing party, allows parties to learn from the most obviously electorally successful incumbents. It therefore enhances the cross-national diffusion of party programs. To test this expectation, we analyze parties’ policy positions in twenty-six established democracies since 1977. Our results indicate that parties disproportionately learn from and emulate dominant, high-clarity foreign incumbents. This finding contributes to a better understanding of the political consequences of government clarity and sheds new light on the heuristics that engender party-policy diffusion by demonstrating that the most visible foreign incumbents, whose platforms have yielded concentrated power in office, influence party politics “at home.”
