Recently there has been a convergence of party funding regimes across Western Europe. The driving force behind this process has been the introduction of state funding to political parties. Why is state funding to political parties being introduced in ever more countries and yet in some places it has only been introduced to a decidedly small degree? This book argues that a consensus of the relevant parties is a prerequisite for the introduction of state funding. The book therefore supposes a nexus between party competition and the outcome of party funding reforms. The introduction of state funding becomes more likely if parties have a high number of institutional veto points at their disposal, if vote-seeking plays a less significant role in parties' strategic preferences than does policy-seeking and office-seeking, and if the discourse on political corruption identifies state funding as a remedy against corrupt practices in party politics. This is confirmed for Germany, Sweden, Britain, and France. Two constellations facilitate the introduction or reform of state subsidies: In political systems which provide parties with a considerable number of veto points, vote-seeking generally plays no central role in decisions about party funding. However, parties can also reach a consensus independently from the institutional environment and their strategic preferences through the discourse on political corruption. There is evidence that causal mechanisms similar to those identified in the four cases studied in the proposed book are at work in Western Europe in general. Thus, the book represents a first step towards a theory which explains differences and similarities of party funding regimes.