Despite established benefits in free trade, protectionism persists to varying degrees across the world. Why is that? Political institutions govern the ways in which competing tradepolicy preferences are aggregated, shaping policy outcomes. The ubiquitous binary PR/ plurality indicator in the trade-politics literature is divorced from comparative institutional research. We build on the latter body of research to generate a new 13-point index that captures the extent to which electoral systems incentivize personal-vote cultivation, based on a combination of established theoretical and new empirical evidence on candidate incentives. We argue that institutional incentives to pursue a personal vote are positively linked to the provision of particularistic policies, including trade protectionism. We find strong empirical support for the hypothesized relationship, and our results highlight the importance of applying parsimonious approaches to studying domestic institutions when analyzing their impact on foreign economic policy.