Despite widespread concern over heated diplomatic debates and growing interest in public diplomacy, it is still incompletely understood what type of message is more effective for gaining support from foreign public, or the international society, in situations where disputing countries compete in diplomatic campaigns. This study, through multiple survey experiments, uncovers the effect of being silent, issuing positive justification, and negative accusation, in interaction with the opponent's strategy. We demonstrate that negative verbal attacks work and undermine the target's popularity as they do in electoral campaigns. Unlike domestic electoral campaigns, however, negative diplomacy has little backlash and persuades people to support the attacker. Consequently, mutual verbal fights make neither party more popular than the other. Nevertheless, this does not discourage disputants from waging verbal fights due to the structure similar to the one-shot prisoner's dilemma. We also find that positive messages are highly context-dependentthat is, their effects greatly depend on the opponent's strategy and value proximity between the messenger and the receiver.

Many scholars argue that economic interdependence and more extensive economic ties between countries decreases the risk of violent conflict between them. However, despite considerable research on the capitalist peace at the macro or dyadic level, there has been less attention to its possible individual-level microfoundations or underpinnings. We argue that public perceptions about economic ties with other states and the costs of conflict should influence the expected constraints on the use of force for leaders. Actual high interdependence and potential economic costs may not suffice to create political constraints on the use of force if people are unaware of the degree of interdependence or fail to understand the benefits of trade and the likely economic costs of disruptive conflict. We examine the linkages between individual perceptions about economic interdependence and their views on conflict and peace through a survey experiment, where we ask respondents in Japan about approval for belligerent actions in a territorial dispute with China and varying information about economic ties. Our findings indicate that greater knowledge and information about economic interdependence affects attitudes about territorial disputes and increases support for peaceful solutions with China.

Which factors drive the onset of genocidal violence? While the previous literature identified several important influences, states' military capabilities for conducting mass-killings and the structure of their security forces have received surprisingly little attention so far. The authors take this shortcoming as a motivation for their research. A theoretical framework is developed, which argues that more differentiated security forces, that is, forces that are composed of a higher number of independent paramilitary and military organizations, are likely to act as a restraint factor in the process leading to state-sponsored mass-killings. Quantitative analyses support the argument for a sample of state-failure years for 1971-2003, and it is also shown that considering a state's security force structure improves our ability to forecast genocides.

Several studies have claimed that changes in the political leadership of a country affect foreign policy decision making. The following paper systematically tests this in the context of states' participation in military coalition operations. By building on previous theoretical models, the authors argue that new leaders may differ from their predecessors in that the former (i) have dissimilar preferences with regard to the involvement in military interventions, (ii) evaluate relevant information differently, and (iii) are less likely to be entrapped in intervention policies. Ultimately, the net effect of these factors should make it more likely that political leadership turnovers are associated with premature withdrawals from ongoing military coalitions. The theory is tested by quantitative analyses of newly collected data on military coalition operations in 1946-2001 and a qualitative case study. The authors find strong and robust support for their argument.

Existing research emphasizes how United Nations Security Council (UNSC) approval helps convey information to domestic audiences that military action is conducted with good intentions, for desirable consequences and in a legitimate manner. This information transmission mechanism can also increase support for UNSC-endorsed military action in countries unlikely to provide major contributions to military actions. There is some cross-national evidence supporting the information transmission mechanism in the United States. Examining the causal mechanisms underlying foreign public support for US military action through a survey experiment with approximately 2,000 respondents in Japan shows that foreign public support varies depending on whether the military action has UNSC approval. The process of presenting draft resolutions to the UNSC also affects public support.

When it comes to buying military aircraft, what leads states to prefer one supplier over the other? This paper explores this question from the perspective of international relations theory. First we use social network analysis to map out fighter jet transfers during and after the Cold War and examine the extent to which historical structures of international hierarchy shape contemporary supplier-receiver relationships. Next, we use a basic probit model to analyse the origins of fighter jets in the world's air forces today to evaluate the effect of interstate orders of super-ordination and sub-ordination on sourcing patterns. All things being equal, the more a state is embedded in US security and economic hierarchy, the more it is likely to buy American-made fighter jets.

The United States uses two forms of multilateralism to increase levels of foreign public support for military action: diplomatic multilateralism and operational multilateralism. Diplomatic multilateralism is typically done by obtaining a United Nations Security Council resolution authorizing military action. The use of multinational forces, the so-called coalition of the willing and many flags program, is an example of operational multilateralism. While scholars have empirical evidence that diplomatic multilateralism generates foreign domestic support for the use of force, there is no equivalent study for operational multilateralism. We do not know if or how much the two types of multilateralism would differ in inducing foreign domestic support for military action. This article, by using Japan as a field of survey experiment, answers these questions.

The use of force is prohibited under the UN Charter. An exception is written in Article 51, which allows a state to conduct an act of self-defense. This study explains why only some states invoke it. The author claims that the baseline probability of claiming the right remains low because explicit reference to Article 51 accompanies the uncertainty of justification success and poses legal and diplomatic costs. However, balanced escalation and no alliance relationship negate those costs and increase the likelihood of self-defense justification. Moreover, under the strict conditionality, minor powers receiving American military aid frequently and promptly claim self-defense.

The export of arms belongs to the most contested issues in democracies. In this article, we examine the economic repercussions of the recent easing of the Japanese arms exports restrictions. We develop a rational expectations argument to understand why some political events increase the income of the arms manufacturers, while other ones reduce it or have no effect at all. Event studies suggest that investors closely observe relevant political developments since stock prices of the six arms manufacturers companies reacted consistently to the announcements and leaks as to whether the arms export restrictions would be lifted or not.

This article aims to demonstrate that differences in the two major datasets can significantly affect the results of predictions of mass political killing. Mass political killing (such as Hitler's killing of some six million Jews, or the Rwanda genocide of 1994) has been studied for decades with the aid of valuable datasets measuring 'democide' and 'genocide and politicide', respectively. Without attempting to take sides as to whether one or the other is a more valid measure of the phenomenon of mass political killing, the authors aim in this investigation to see what independent variables best account for the onset of mass political killing, with the state-year as the unit of analysis. The predictor variables are level of economic development; types of war and violent unrest short of war; and regime type. By using a Cox proportional hazard model, the authors find that important regime effects either appear or disappear depending on the dataset used, with regime generally having a significant effect on onset of democide, but not having a significant effect on onset of geno-politicide. It is important for the scholarly community to be aware of these dataset effects, which may be the source of some of the most important existing controversies in the literature on explaining mass political killing.

This article aims to demonstrate that differences in the two major datasets can significantly affect the results of predictions of mass political killing. Mass political killing (such as Hitler's killing of some six million Jews, or the Rwanda genocide of 1994) has been studied for decades with the aid of valuable datasets measuring 'democide' and 'genocide and politicide', respectively. Without attempting to take sides as to whether one or the other is a more valid measure of the phenomenon of mass political killing, the authors aim in this investigation to see what independent variables best account for the onset of mass political killing, with the state-year as the unit of analysis. The predictor variables are level of economic development; types of war and violent unrest short of war; and regime type. By using a Cox proportional hazard model, the authors find that important regime effects either appear or disappear depending on the dataset used, with regime generally having a significant effect on onset of democide, but not having a significant effect on onset of geno-politicide. It is important for the scholarly community to be aware of these dataset effects, which may be the source of some of the most important existing controversies in the literature on explaining mass political killing.

Why do some democracies break their security commitments whereas others do not? This study proposes a research strategy to answer the question by analyzing the timing of unilateral exits from a coalition military operation. Coalition participants typically do not exit until a military mission has been accomplished. However, in the case of the US-led coalition occupying Iraq since May 2003, 16 states have unilaterally withdrawn their armed forces. Despite the danger such defections may cause to the relationship of these states with the USA, why and when do they exit? The author creates a dataset with a state-month unit of analysis that contains information on 37 partner states and applies a Cox proportional hazard model. The study finds that the occurrence of a national election serves as a strong driving force to accelerate an exit from the coalition. An incumbent leader who faces a challenger who opposes military contributions in Iraq would reverse the policy to support the USA and exit the coalition to win an election, even at the risk of damaging a bilateral relationship with the USA. A change in leadership after an election, on the other hand, failed to be a predictor of the timing of defection. Furthermore, results reveal that the division of power within the government and the constitutional rules that enable significant parliamentary control over executive decisions to use force neither delay nor accelerate the timing of withdrawal. To understand the conditions under which democracies break their security commitments, more attention should be paid to election cycles than to a change in leadership and to types of democratic institutional and constitutional arrangements.

Why do some democracies break their security commitments whereas others do not? This study proposes a research strategy to answer the question by analyzing the timing of unilateral exits from a coalition military operation. Coalition participants typically do not exit until a military mission has been accomplished. However, in the case of the US-led coalition occupying Iraq since May 2003, 16 states have unilaterally withdrawn their armed forces. Despite the danger such defections may cause to the relationship of these states with the USA, why and when do they exit? The author creates a dataset with a state-month unit of analysis that contains information on 37 partner states and applies a Cox proportional hazard model. The study finds that the occurrence of a national election serves as a strong driving force to accelerate an exit from the coalition. An incumbent leader who faces a challenger who opposes military contributions in Iraq would reverse the policy to support the USA and exit the coalition to win an election, even at the risk of damaging a bilateral relationship with the USA. A change in leadership after an election, on the other hand, failed to be a predictor of the timing of defection. Furthermore, results reveal that the division of power within the government and the constitutional rules that enable significant parliamentary control over executive decisions to use force neither delay nor accelerate the timing of withdrawal. To understand the conditions under which democracies break their security commitments, more attention should be paid to election cycles than to a change in leadership and to types of democratic institutional and constitutional arrangements.

There is an empirical evidence of an aid-for-policy deal between the United States and other states; the United States has utilized aid programs to promote affirmative votes in the UN General Assembly and to maintain an alliance relationship with strategically important states. However, whether there is a systematic evidence of an aid-for-participation deal remains inconclusive. Does the United States generally utilize its foreign aid to reward the contribution of troops to the US-led multinational forces and to punish the lack of contribution? The author argues that US foreign aid is used to prevent free-riding in coalition participation. To test the argument, I examined whether states were punished or rewarded by the United States for their behavior in sending or failing to send troops to 15 post-Second World War US-led coalition forces. The results show that the United States punished states for unexpected nonparticipation, but did not always provide rewards for support.

There is an empirical evidence of an aid-for-policy deal between the United States and other states
the United States has utilized aid programs to promote affirmative votes in the UN General Assembly and to maintain an alliance relationship with strategically important states. However, whether there is a systematic evidence of an aid-for-participation deal remains inconclusive. Does the United States generally utilize its foreign aid to reward the contribution of troops to the US-led multinational forces and to punish the lack of contribution? The author argues that US foreign aid is used to prevent free-riding in coalition participation. To test the argument, I examined whether states were punished or rewarded by the United States for their behavior in sending or failing to send troops to 15 post-Second World War US-led coalition forces. The results show that the United States punished states for unexpected nonparticipation, but did not always provide rewards for support. © The author [2008]. Published by Oxford University Press in association with the Japan Association of International Relations
all rights reserved.

Why do states join US-led military coalitions? The war/dispute-diffusion literature suggests that opportunity and willingness are crucial determinants of coalition participation (Siverson snd Starr.1990, 1991). A state joins a coalition if it has a strong interest in war and enough capability to send armed forces abroad. Alliance studies connect coalition participation problems with the reliability of allied countries (Leeds, 2003 Gartzke and Gleditsch, 2004). These studies seem to provide a fairly good picture on the question
however, they are not free of problems. In particular, they study only coalitions for interstate war and militarized disputes but ignore coalitions for other purposes. Coalitions can be formed for military operations other than war (Kober, 2002). There are coalitions for humanitarian intervention, peacekeeping, and even for the evacuation of noncombatants. This article shows how difference in operation-types and collective legitimacy affect the decision of a state to participate in US-led coalitions. A coalition with United Nations' authorization may appear to be a legitimate international 'police' act and attract more partner states. A coalition for intervention into domestic affairs may be less attractive to possible participants because of the violation of the noninterference norm of international law. Statistical analysis on United States coalition partners from 1950 to 1999 suggests that how and for what purposes coalitions are formed cannot be overlooked. Coalition participation is not fully explained by the existing perspectives found in war/dispute-diffusion literature and alliance studies, and there is a need to invok 'the compulsion of the coalition's missions and legitimacy'. © The author [2007]. Published by Oxford University Press in association with the Japan Association of International Relations
all rights reserved.

Why do states join US-led military coalitions? The war/dispute-diffusion literature suggests that opportunity and willingness are crucial determinants of coalition participation (Siverson and Starr, 1990, 1991). A state joins a coalition if it has a strong interest in war and enough capability to send armed forces abroad. Alliance studies connect coalition participation problems with the reliability of allied countries (Leeds, 2003; Gartzke and Gleditsch, 2004). These studies seem to provide a fairly good picture on the question; however, they are not free of problems. in particular, they study only coalitions for interstate war and militarized disputes but ignore coalitions for other purposes. Coalitions can be formed for military operations other than war (Kober, 2002). There are coalitions for humanitarian intervention, peacekeeping, and even for the evacuation of noncombatants. This article shows how difference in operation-types and collective legitimacy affect the decision of a state to participate in US-led coalitions. A coalition with United Nations' authorization may appear to be a legitimate international 'police' act and attract more partner states. A coalition for intervention into domestic affairs may be less attractive to possible participants because of the violation of the noninterference norm of international law. Statistical analysis on United States coalition partners from 1950 to 1999 suggests that how and for what purposes coalitions are formed cannot be overlooked. Coalition participation is not fully explained by the existing perspectives found in war/dispute-diffusion literature and alliance studies, and there is a need to invoke 'the compulsion of the coalition's missions and legitimacy'.

US presidents used military force 212 times from 1948 to 1998. In 45 of these cases, the force was embedded in a multilateral context. The article distinguishes between procedural multilateralism, where US military operations are endorsed by an international organization, and operational multilateralism, where military actions are coordinated with the armed forces of other countries. In some cases, such as the Korean War and the first Gulf War, the United States obtained UN authorization and created a multinational force. However, there are also partially multilateral cases, in which either political endorsement or execution of the use of force is made by a multilateral approach while the other is subject to unilateralism. This article focuses on the varieties of multilateralism and homes in on exploring why such varieties of multilateralism exist. An original dataset for studying multilateral-unilateral choice in US use of force is analyzed using a multinomial logit model and a bivariate probit model. The analyses suggest that three domestic conditions - recession, election cycle, and divided government - can cause partial multilateralism, since they create different incentives for the president to seek burden-sharing with allies or seek collective legitimacy in international organizations. © 2005 Journal of Peace Research.

US presidents used military force 212 times from 1948 to 1998. In 45 of these cases, the force was embedded in a multilateral context. The article distinguishes between procedural multilateralism, where US military operations are endorsed by an international organization, and operational multilateral ism, where military actions are coordinated with the armed forces of other countries. In some cases, such as the Korean War and the first Gulf War, the United States obtained UN authorization and created a multinational force. However, there are also partially multilateral cases, in which either political endorsement or execution of the use of force is made by a multilateral approach while the other is subject to unilateralism. This article focuses on the varieties of multilateralism and homes in on exploring why such varieties of multilateralism exist. An original dataset for studying multilateral-unilateral choice in US use of force is analyzed using a multinomial logit model and a bivariate probit model. The analyses suggest that three domestic conditions - recession, election cycle, and divided government - can cause partial multilateralism, since they create different incentives for the president to seek burden-sharing with allies or seek collective legitimacy in international organizations.