How does ballot structure affect party choice? We argue that open lists undermine the electoral support of cohesive parties, to the benefit of internally divided parties. We conduct a survey-embedded experiment in the aftermath of the European migrant crisis, presenting German voters with real parties but fictitious politicians. A crossover design varies ballot type and exposure to candidate positions on immigration. We find that the internally divided Christian Democrats gain votes at the expense of the cohesive Alternative for Germany when open lists are used and candidate positions are known. For individuals who are equally attracted to both parties, switching is most likely if their immigration preferences lie near the midpoint between the two parties. Overall, our analysis establishes conditions under which ballot structure can affect the electoral performance of parties in general, and that of the populist right in particular.

Models of ideal point estimation usually build on the assumption of spatial preferences. This ignores legislators' non-policy incentives and is thus likely to produce implausible results for many legislatures. We study this problem in parliamentary systems and develop a model of roll call voting that considers both the policy and the non-policy, tactical incentives of legislators. We go on to show how the relative weight of these policy and tactical incentives is influenced by the identity of the mover and characteristics of the motion. Analyses of two data sets of 2174 roll call votes in German state legislatures and 3295 roll call votes in the British House of Commons result in three main findings. First, we show that tactical incentives may be more important than policy incentives, and second, that the importance of tactical incentives varies with the importance of motions. Third, there are interesting twists: backbench private members' bills may reverse tactical incentives whereas proposals from anti-system parties are virtually always rejected by moderate parties, rendering these votes uninformative. Our findings have implications for ideal point estimation in parliamentary systems, as well as for research on separation of power systems.

Party competition is largely about making policy promises to voters. We argue that the clarity of the expressed policy position may be equally important. If blurred messages toward different audiences and therefore ambiguous positions can attract votes from different groups, parties have incentives to present ambiguous rather than clear-cut policy platforms. We present a formal model of multi-party competition with stochastic voting where party leaders make strategic choices on both the position and the level of ambiguity of their platforms. Leaders respond to the demands of two principals, the general public and party core constituencies. We derive two hypothesis on the location and ambiguity of party platforms and provide initial tests of these hypotheses in a comparative setting in 14 Western European democracies gathering data on voter and party left-right positions from Eurobarometer surveys and electoral manifestos. Ambiguity of party profiles is estimated using a variant of Wordscores on a newly established data set of electoral manifestos. We find that platforms become more ambiguous as the preferences of the two principals diverge. Our findings imply that ambiguity can be a winning strategy for parties, especially in settings with strong partisan lines.

Various strands of literature in comparative politics suggest that there is a differential impact of the type of government and their supporting legislative coalitions in parliamentary democracies, for example, in terms of their size and ideological heterogeneity, and on their potential to induce policy change. Most studies in this area focus on governments as agenda-setters, possibly neglecting the role of parliaments as a further key actor in policy making. In this article, we address the broader question as to how patterns of conflict within parliament effect legislative activity of governments and parliamentary actors. Through a simultaneous analysis of the success and event history of over 12,000 legislative bills in three parliamentary systems and one semi-presidential system from 1986 until 2003, we show how the interplay of actor motivations and institutional settings has a discriminating impact on the potential of both the government and parliament to induce policy change.

This article analyses the origins and consequences of multicameral representation and voting in international organizations. It is argued that the existence of visible and durable conflicts in an issue area can make standard procedures such as unicameral majority voting ineffective with respect to the functioning of the regime. Applying spatial models of strategic decision making, it is asserted that multicameralism is more likely to be effective than unicameralism if chambers consist of key groups with distinct interests. Empirical evidence is provided by studying the multicameral voting rule in the Council of the International Seabed Authority (ISA). I compare likely decision-making outcomes under unicameral and multicameral voting rules from 1996 to 2002 and find that multicameral outcomes are more likely to be stable and supported by those actors critical for the effective functioning ofthe regime.