This study examines the influence of civil–military relations on military effectiveness. More specifically, we investigate how coup-proofing, that is, the strategies and tactics employed to prevent the military from seizing power, affects battlefield performance. The main argument claims that coup-proofing has a negative impact on soldiers’ leadership qualities, initiative, and the ability to coordinate different military units. Ultimately, the higher a country’s coup-proofing efforts relative to its opponent, the worse its effectiveness on the battlefield. We test this hypothesis using data on battlefield outcomes and coup-proofing between 1967 and 1999.

Do parties learn from or emulate parties in other political systems? This research develops the argument that parties are more likely to employ the heuristic of learning from and emulatingforeign successful (incumbent) parties. Spatial-econometric analyses of parties’ election policies from several established democracies robustly confirm that political parties respond to left-right policy positions of foreign political parties that have recently governed. By showing that parties respond to theseforeign incumbent parties, this work has significant implications for our understanding of party competition. Furthermore, we contribute to the literature on public policy diffusion, as we suggest that political parties are important vehiclesthroughwhich public policies diffuse.

This article reviews the existing theoretical arguments and empirical findings linking renewable and non-renewable natural resources to the onset, intensity, and duration of intrastate as well as interstate armed conflict. Renewable resources are supposedly connected to conflict via scarcity, while non-renewable resources are hypothesized to lead to conflict via resource abundance. Based upon our analysis of these two streams in the literature, it turns out that the empirical support for the resource scarcity argument is rather weak. However, the authors obtain some evidence that resource abundance is likely to be associated with conflict. The article concludes that further research should generate improved data on low-intensity forms of conflict as well as resource scarcity and abundance at subnational and international levels, and use more homogenous empirical designs to analyze these data. Such analyses should pay particular attention to interactive effects and endogeneity issues in the resource–conflict relationship.

A recent Climatic Change review article reports a remarkable convergence of scientific evidence for a link between climatic events and violent intergroup conflict, thus departing markedly from other contemporary assessments of the empirical literature. This commentary revisits the review in order to understand the discrepancy. We believe the origins of the disagreement can be traced back to the review article's underlying quantitative meta-analysis,

The existing literature on military effectiveness established the robust claim that democracies are more successful and effective in winning interstate wars. One mechanism that explains this relationship heavily draws upon the underlying effect of regime type on civil–military relations. Still, this relationship has not yet been explored systematically, and rigorous empirical research on this issue remains surprisingly scarce. In order to address this shortcoming, this study investigates the patterns of civil–military relations according to different regime types, that is, democracies and nondemocracies. More specifically, the authors examine whether and how democracies invest in coup‐proofing, that is, strategies employed to prevent the military from seizing power. The main argument is derived from a principal‐agent logic and claims that coup‐proofing is both a relatively less attractive and necessary instrument for democratic principals. By analyzing newly compiled time‐series cross‐sectional data on states’ coup‐proofing efforts in 1975–1999, the core hypothesis is tested in a quantitative framework.

There is a heated debate on whether immigration is associated with domestic and transnational terrorism. As of yet, however, we lacked rigorous evidence that could inform this debate. As a contribution to address this shortcoming, we report spatial-econometric analyses of migrant inflows and the number of terrorist attacks in 145 countries between 1970 and 2000. The results suggest that migrants stemming from terrorist-prone states moving to another country are indeed an important vehicle through which terrorism does diffuse. Having said that, the findings also highlight that migrant inflows per se actually lead to a lower level of terrorist attacks. This research significantly improves our understanding of international and domestic terrorism, and has critical implications for the scholastic approach to terrorism as well as for countries' immigration policies worldwide.

This letter reviews the scientific literature on whether and how environmental changes affect the risk of violent conflict. The available evidence from qualitative case studies indicates that environmental stress can contribute to violent conflict in some specific cases. Results from quantitative large-N studies, however, strongly suggest that we should be careful in drawing general conclusions. Those large-N studies that we regard as the most sophisticated ones obtain results that are not robust to alternative model specifications and, thus, have been debated. This suggests that environmental changes may, under specific circumstances, increase the risk of violent conflict, but not necessarily in a systematic way and unconditionally. Hence there is, to date, no scientific consensus on the impact of environmental changes on violent conflict. This letter also highlights the most important challenges for further research on the subject. One of the key issues is that the effects of environmental changes on violent conflict are likely to be contingent on a set of economic and political conditions that determine adaptation capacity. In the authors' view, the most important indirect effects are likely to lead from environmental changes via economic performance and migration to violent conflict.

Civil society is commonly assumed to have a positive effect on international cooperation. This paper sheds light on one important facet of this assumption: we examine the impact of environmental non-governmental organizations (ENGOs) on ratification behavior of countries vis-à-vis international environmental agreements (IEAs). The main argument of the paper focuses on a “democracy-civil society paradox”: although ENGOs have a positive effect on ratification of IEAs on average, this effect decreases with increasing levels of democracy. This argument is counter-intuitive and appears paradoxical because democracy is generally associated both with a more active civil society and more international cooperation. The reasons for this hypothesized effect pertain to public demand for environmental public goods provision, government incentives, and problems of collective action among ENGOs. To test the net effect of ENGOs on countries' ratification behavior, the paper uses a new dataset on ENGOs in the time-period 1973–2006. The results offer strong support for the presumed democracy–civil society paradox.