Who sets lawmakers' priorities? The aim of the thesis is to provide a convincing theoretical argument able to identify what are the policy problems that demand lawmakers' attention, but also to test this empirically for France, Denmark, Spain and the United Kingdom between 1980 and 2008. This research shows how accounting for the way in which lawmakers deal with competing policy problems integrate two major accounts of the way in which governments set their priorities: party mandate approaches and public policy approaches. The thesis does so by suggesting that given their double role of representatives and administrators, lawmakers have to deliver policies consistent both with electoral and non-electoral mandates. In this framework, parties’ promises, administrative commitments, and the priorities of the public originate policy problems that compete for lawmakers' attention to enter the policy agenda. Compared to classic party mandate approaches, this research does not conceive parties as being the key actors of the game or the major agenda-setters. Compared to public policy approaches, the study does not dismiss the role of parties. The theory argues that a problem-solving approach is key to account for lawmakers' priorities and for the way in which lawmakers select policy problems that need to be addressed in the policy agenda. In this framework, different policy problems demand lawmakers' attention and problems-solving scholars have illustrated that the types of issues that need to be addressed are different in "nature". Existing accounts of the composition of policy agendas distinguish between problems ranging from "compulsory" to "discretionary" concerns (Walker 1977; Adler and Wilkerson 2012) where the former derive from "periodically recurring demands " and the latter from "chosen problems" (Walker 1977:425). Building on these contributions, the theoretical model of the dissertation discusses the "nature" of different policy problems by identifying some 'ideal types' that originate from the double functions that lawmakers shall perform in contemporary democracies as "representatives" of voters' interests and as "responsible" administrators (Mair 2009). In this sense, the dissertation contends that different policy problems emerge from the electoral promises of the governing parties, from commitments related to the responsibility of being in office, and from the 'external world', and that the balance between them determines the composition of the policy agenda. 13 There are four propositions of this study to existing knowledge in the field of policy agendas. The first is that the content of the policy agenda is stable across countries with different institutional settings. Lawmakers' priorities are no less stable in institutional systems that are more 'open' to accommodating policy problems brought by the electoral promises of the parties. At the same time stability persists even when elections approach, questioning the long-lasting assumption that lawmakers may manipulate policies to their will in order to assure re-election. The second is that policy problems brought by the electoral promises of the governing parties impact lawmakers’ priorities, but this is only half of an old story. The results show that the policy problems originating from the electoral promises of the opposition influence the content of the policy agenda confirming that the agenda-setting power of parties is not limited to those who are in office. The third proposition is a theoretical effort and empirical contribution to conceptualise and measure "policy commitments". Studies of public policy have stressed the importance of inherited commitments in everyday law making (Rose 1994; Adler and Wilkerson 2012) since some decisions take longer than a legislature to be realised. Classic analyses have emphasised the importance of budgetary constraints on policy agendas, but the thesis suggests that there is also another striking case of policy commitments for European polities: EU integration, since decisions on EU affairs and delegation of powers taken from previous governments are hard (if not impossible) to reverse by their successors. In this sense, EU decisions are inherited by all governments, and they add complexity to the problem-solving capacity of Member States because they produce extra policy problems that require lawmakers' attention. For lawmakers respecting legally binding EU decisions, this is a way to avoid "reckless and illegal decision making" (Mair 2009). The results highlight that when reflecting on the divisions of competences between the Union and its Member States (MSs), policy commitments derived from the EU directives are concentrated on a narrow set of policy areas. The results show that in most fields where commitments are higher, the agenda-setting power of parties’ electoral promises is weakened. Finally, this research suggests that policy problems originating from the agenda of the public (as approximated by media coverage) are another explanatory factor of policy priorities, but in a very narrow set of policy areas. Media effects appear to be limited to policy areas with the special characteristics of newsworthiness and sensationalism (Soroka 2002) that contribute to boost their policy appeal. In addition, the findings highlight that the agenda-setting power of the media is mediated by the interaction with the electoral promises of the opposition, probably as a result of a blame avoidance game to discredit incumbents. 14 Chapter 1 introduces the concepts of policy agenda and policy problem before summarising existing accounts of the content of policy agendas. Two theoretical traditions are identified. The first one is the "partisan account" highlighting the importance of partisan preferences for lawmakers' priorities. The second is made up of the "public policy accounts" proposing incrementalist and agenda-setting approaches to representatives' priorities. Chapter 2 sets up the theoretical framework that will be tested in this research. Drawing upon theories of "representative and responsible" government (Mair 2009) the research provides an encompassing model of how different policy problems compete for attention in order to enter the agendas of lawmakers. The thesis highlights that different agenda-setters have to be considered as creating policy problems: the electoral promises of the governing parties, the demands addressed to lawmakers by the EU agenda, and the issues that are important for the public as reported by the media. Starting from existing typologies of problems that must be addressed in the policy agenda (Walker 1977; Adler and Wilkerson 2012), the research roughly distinguishes between discretionary and compulsory policy problems, discussing how the three agenda-setters considered in this study fit into those ideal types, as well as the incentives for lawmakers to prioritise one over the other. Chapter 3 presents the data, models and methods that are used to test the theoretical framework. The dissertation relies on data from the Comparative Agendas Project modelled in the form of time series cross sectional models. Chapter 4 introduces the empirical investigation of the content of the policy agenda. It focuses on stability and change in lawmakers' priorities, to understand the extent to which priorities change (or remain the same) across elections. Chapter 5 moves a step further and will assess the connection between policy problems brought by parties' electoral promises and the content of the policy agenda. Chapter 6 will account for one of the most debated sources of policy problems among public policy scholars: policy commitments. This chapter will test the agenda-setting power of policy commitments deriving from the content of the EU directives on lawmakers' priorities and proposing an "EU acquiescence index" to shed light on the 'overlaps' between EU and domestic policy agendas. Finally, Chapter 7 aims at analysing the connection between lawmakers' priorities and media coverage (in terms of print and, where appropriate, audio media) and each of the two relevant types of policy problems competing for lawmakers' attention identified in the previous chapters. In sum the thesis offers a theory of the composition of policy agendas grounded in a problem-solving understanding of politics, and an empirical assessment of its validity. In this sense the study is about how policy problems originating from the dual role of lawmakers in 15 contemporary democracies (representation and administration) affect everyday policy making. More precisely the thesis considers the impact of different agenda venues (parties, EU commitments, and the media) on the way in which lawmakers deliver policies.