Eight months after adoption, less than 60 per cent of the country-specific recommendations are partially or fully implemented, and the performance has worsened after the introduction of the European Semester (ES). This chapter employs political economy theories of reform to explain differences in implementation, analyzing the full set of recommendations released between 2002 and 2019. A combination of economic and electoral pressures as well as the costs of noncompliance are associated with these patterns. Proximity to electoral contests lowers the rates of implementation, even though this effect weakens under the ES. In 2002–2010, inflationary pressures acted as drivers of compliance in euro area countries and as obstacles to compliance in non-euro area countries. After the introduction of the ES, the sovereign debt crisis triggered fuller implementation. Moreover, governments adopted especially those actions that were associated with a more established supranational system for sanctioning noncompliance. Raw country power has had different implications. Countries with higher voting power were initially less compliant. Later on, economically larger countries complied more.