Competition among partisan projects is often cited as a constitutive element of all representative democracies. While the Francophone and English-medium research literature have viewed the link between partisan competition and public policy differently, in both cases parties tend to be the “poor cousins” of theories of public action. Drawing from theories of agenda-setting and issue competition, this article argues for taking the partisan variable more seriously, by adopting an approach which is both global and differentiated and which aims to establish in what conditions governing parties influence public policies. Data from the Comparative Agendas Project provide a challenging basis for investigating this issue. Testing several hypotheses concerning French legislative activities between 1981 and 2009 highlights its potentialities.