Drawing on a panel of 136 countries over the period 1982–2004, we study a tipping point version of Vogel's ‘California Effect’ in the context of the diffusion of human rights practices. Because human rights practices are often deeply embedded in a society's customs and political institutions, we expect that a high level of pressure from the importing countries is needed to bring about changes in an exporting country's human rights records. We find strong empirical support for this threshold effect; provided that the average level of respect for human rights in importing countries is sufficiently high, trading relationships can operate as transmission belts for the diffusion of human rights practices from importing to exporting countries.

Religion can be a source of undemocratic attitudes but also a contributor to democratic norms. This article argues that different dimensions of religiosity generate contrasting effects on democratic attitudes through different mechanisms. The private aspect of religious belief is associated with traditional and survival values, which in turn decrease both overt and intrinsic support for democracy. The communal aspect of religious social behaviour increases political interest and trust in institutions, which in turn typically lead to more support for democracy. Results from multilevel path analyses using data from fifty-four countries from Waves 4 and 5 of the World Values Survey suggest there is some regularity in mechanisms responsible for the effect of religiosity on democratic support that extend beyond religious denomination.

This article tests several hypotheses about distributive politics by studying the distribution of federal spending across US states over the period 1978–2002. It improves on previous work by using survey data to measure the share of voters in each state that are Democrats, Republicans and Independents, or liberals, conservatives and moderates. No evidence is found that the allocation of federal spending to the states is distorted by strategic manipulation to win electoral support. States with many swing voters are not advantaged compared to states with more loyal voters, and ‘battleground states’ are not advantaged compared to other states. Spending appears to have little or no effect on voters’ choices, while partisanship and ideology have large effects.

The authors contribute to the existing literature on the determinants of legislative voting by offering a social network-based theory about the ways that legislators’ social relationships affect floor voting behaviour. It is argued that legislators establish contacts with both political friends and enemies, and that they use the information they receive from these contacts to increase their confidence in their own policy positions. Social contacts between political allies have greater value the more the two allies agree on policy issues, while social contacts between political adversaries have greater value the more the two adversaries disagree on policy issues. To test these propositions, we use social network analysis tools and demonstrate how to account for network dependence using a multilevel modelling approach.

An implicit element of many theories of constitutional enforcement is the degree to which those subject to constitutional law can agree on what its provisions mean (call this constitutional interpretability). Unfortunately, there is little evidence on baseline levels of constitutional interpretability or the variance therein. This article seeks to fill this gap in the literature, by assessing the effect of contextual, textual and interpreter characteristics on the interpretability of constitutional documents. Constitutions are found to vary in their degree of interpretability. Surprisingly, however, the most important determinants of variance are not contextual (for example, era, language or culture), but textual. This result emphasizes the important role that constitutional drafters play in the implementation of their product.

While Europarties have received increasing attention in recent years, little is known about how they arrive at common policy positions, given their strong internal ideological heterogeneity. In order to explain position formation within Europarties, this article argues that national parties compete with each other in an attempt to upload their own policy positions to their Europarty. The article hypothesizes that their ability to succeed in these attempts depends on their legislative resources. The argument is tested by analysing position formation within the four major Europarties for all European Parliament elections between 1979 and 2004. The empirical results confirm that position choice is skewed towards parties with a large seat share, which has important implications for political representation in Europe.

The likelihood of conflict and the observation of joint democracy tend to cluster regionally. This article tests the argument that these clusters can be explained by regional variations in the stability of international borders using a new dataset of territorial dispute hot spots from 1960–1998. These hot spots identify spatial and temporal correlations in the territorial dispute data and therefore serve as close proxies for regional or neighbourhood instability. The addition of these hot spots also eliminates a common form of omitted variable bias – the spatial clustering of conflict – in international conflict models. These results confirm that joint democracy is only statistically significant as a predictor of fatal militarized interstate disputes in more peaceful neighbourhoods once territorial hot spots are jointly estimated. The interaction between joint democracy and regional instability confirms that the effects of regime type on continued conflict apply mostly to dyads in peaceful regions.

A large number of studies of ideological congruence, and of the effect of public opinion on policy outcomes more generally, have relied on the Kim-Fording (KF) measure of median voter opinion. This measure has the great virtue of being readily calculable – no direct measurement of voter opinion is required – but it rests on assumptions concerning party locations and voter behaviour that are unquestionably incorrect, at least some of the time. This article explores the sensitivity of the KF measure to violations of its core assumptions through simulation experiments. It then uses public opinion data to assess the degree to which consequential levels of violation occur in actual democratic systems. The article concludes with a discussion of what the KF median really measures and where it can – and cannot – be safely used.

Are voting rights a class or an ethnic issue? They are both in the diverse societies of the developing world, yet the salience of ethnicity in public discourse frequently compels people to articulate identity demands that may be inconsistent with their material interests, particularly among the rich. This article examines these ideas with an augmented list experiment about illiterate voting rights in Lebanon. Consistent with received wisdom, direct questions yield identity-based answers in which Shiites are more supportive of voting rights than are Sunnis or Christians. Unobtrusive questions, in contrast, yield answers about material deprivation in which poor people are more supportive of illiterate voting than are rich people. The divergence between public statements and private preferences helps to reconcile theoretical predictions that people respond to material incentives with empirical findings that they pursue identity interests.

Does naming and shaming states affect respect for human rights in those states? This article argues that incentives to change repressive behaviour when facing international condemnation vary across regime types. In democracies and hybrid regimes – which combine democratic and authoritarian elements – opposition parties and relatively free presses paradoxically make rulers less likely to change behaviour when facing international criticism. In contrast, autocracies, which lack these domestic sources of information on abuses, are more sensitive to international shaming. Using data on naming and shaming taken from Western press reports and Amnesty International, the authors demonstrate that naming and shaming is associated with improved human rights outcomes in autocracies, but with either no effect or a worsening of outcomes in democracies and hybrid regimes.

Is democracy a requirement of justice or an instrument for realizing it? This article argues that the correct answer to this question depends on the background circumstances against which democracy is defended. In the presence of thin reasonable disagreement about justice, we should value democracy only instrumentally (if at all); in the presence of thick reasonable disagreement about justice, we should value it also intrinsically, as a necessary demand of justice. Since the latter type of disagreement is pervasive in real-world politics, the conclusion is that theories of justice designed for our world should be centrally concerned with democracy.

Missing values are a frequent problem in empirical political science research. Surprisingly, the match between the measurement of the missing values and the correcting algorithms applied is seldom studied. While multiple imputation is a vast improvement over the deletion of cases with missing values, it is often unsuitable for imputing highly non-granular discrete data. We develop a simple technique for imputing missing values in such situations, which is a variant of hot deck imputation, drawing from the conditional distribution of the variable with missing values to preserve the discrete measure of the variable. This method is tested against existing techniques using Monte Carlo analysis and then applied to real data on democratization and modernization theory. Software for our imputation technique is provided in a free, easy-to-use package for the R statistical environment.

Most research on political representation focuses on how citizens’ ideology and partisanship influence their support for political candidates – leaving the question of whether (and how) elected officials influence citizens’ positions on political issues open to debate. The hypothesis tested here – using a unique, quasi-experimental design with American National Election Study data between 1956 and 2004 – is that Democratic representatives shift the opinions of constituents in the pro-Democratic and liberal direction, while Republican representatives shift constituents’ opinions in the pro-Republican and conservative direction. The findings show that incumbent representatives indeed move their constituents’ opinions in a particular direction, and that representatives have a stronger impact on constituents who are more frequently exposed to their messages.

Over the past fifty years, top political science journals have published hundreds of articles about policy diffusion. This article reports on network analyses of how the ideas and approaches in these articles have spread both within and across the subfields of American politics, comparative politics and international relations. Then, based on a survey of the literature, the who, what, when, where, how and why of policy diffusion are addressed in order to identify and assess some of the main contributions and omissions in current scholarship. It is argued that studies of diffusion would benefit from paying more attention to developments in other subfields and from taking a more systematic approach to tackling the questions of when and how policy diffusion takes place.

Does the diffusion of nuclear programs encourage nuclear and radiological (NR) terrorism? It is argued that a country's vulnerability to NR terrorism grows as the size of its nuclear program increases. The presence of expansive nuclear infrastructure facilitates terrorists’ efforts to steal or acquire nuclear and radiological materials, increases the targets open to attack, and amplifies the potential economic and social-psychological consequences of related terrorist attacks. It is also argued that countries can reduce the likelihood of NR terrorism by improving nuclear security and reducing corruption. An empirical analysis of NR terrorist incidents during 1992–2006 supports for these arguments. The findings offer empirically grounded insights into the future risks of nuclear terrorism, and possible solutions are offered.

In districts where only one seat is contested, the electoral formula (plurality or majority) should be a major determinant of the number of parties that receive votes. Specifically, plurality rule should generate two-party competition while other institutional arrangements should generate electoral fragmentation. Yet tests of these propositions using district-level data have focused on a limited number of cases; they rarely contrast different electoral systems and have reached mixed conclusions. This study analyses district-level data from 6,745 single-member district election contests from 53 democratic countries to test the evidence for Duverger's Law and Hypothesis. Double-ballot majoritarian systems have large numbers of candidates, as predicted, but while the average outcome under plurality rule is generally consistent with two-party competition, it is not perfectly so. The two largest parties typically dominate the districts (generally receiving more than 90 per cent of the vote), and there is very little support for parties finishing fourth or worse. Yet third-place parties do not completely disappear, and ethnic divisions shape party fragmentation levels, even under plurality rule. Finally, institutional rules that generate multiparty systems elsewhere in the country increase electoral fragmentation in single-member plurality districts.

This article discusses recent research on party politics and the welfare state that differs from traditional ‘partisan politics theory’. The traditional approach states that left-wing and right-wing parties hold contrasting positions on welfare issues, depending on the interests of their respective electorates. This view has recently been challenged by three strands of research, which emphasize (1) the effects of electoral change on parties’ policy positions, (2) the role of context, notably electoral institutions, party competition and the configuration of party systems, and (3) the impact of different linkages between parties and electorates (particularistic versus programmatic). The implications of these arguments for the applicability of partisan theory are presented, and theoretical and empirical issues are identified for further research.

Policy-sensitive models of judicial behaviour, whether attitudinal or strategic, have largely passed Britain by. This article argues that this neglect has been benign, because explanations of judicial decisions in terms of the positions of individual judges fare poorly in the British case. To support this argument, the non-unanimous opinions of British Law Lords between 1969 and 2009 are analysed. A hierarchical item-response model of individual judges’ votes is estimated in order to identify judges’ locations along a one-dimensional policy space. Such a model is found to be no better than a null model that predicts that every judge will vote with the majority with the same probability. Locations generated by the model do not represent judges’ political attitudes, only their propensity to dissent. Consequently, judges’ individual votes should not be used to describe them in political terms.