Two substantial dimensions of public policy in industrialized democracies are taxes and public debt. They are closely related: the annual deficit is the difference between government expenditures and government revenues. These variables will be analyzed in this study, while focusing on how parties influence them. Ascertaining the influence of parties on public policies has a long tradition in comparative public policy research. It began in the work of Douglas Hibbs (1977). Within this field there are many other scholars such as Alesina and Rosenthal (1995), Cameron (1978), Castles (1982), Schmidt (1982) and Tufte (1978), to mention only a few. Behind the “parties-do-matter” proposition that all these writers adhere to lies the assumption that there are distinct differences in the ideologies of parties.