How Uncertainty about War Outcomes Affects War Onset

In canonical accounts of war, conflict outcomes are inherently uncertain. Contesting literatures posit that this uncertainty, arising from stochastic elements of the war-fighting process, may induce conflict due to greater risks of miscalculation or foster peace by breeding caution. We theorize that states, on average, exhibit prudence when confronting greater uncertainty. Despite its conceptual importance, extant proxies for uncertainty at various levels of analysis—such as polarity, balance of power, system concentration, and dyadic relative capabilities—are imprecise and theoretically inappropriate indicators. To overcome this shortcoming, we theorize the conditions that elevate the magnitude of uncertainty over conflict outcomes and introduce a novel measure that captures this uncertainty within any k-state system. Through extensive empirical analysis, we confirm uncertainty’s pacifying effect and show how this effect operates at different levels of analysis.Governmen

High levels of SARS-CoV-2-specific T cells with restricted functionality in severe courses of COVID-19

BACKGROUND. Patients infected with severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) differ in the severity of disease. We hypothesized that characteristics of SARS-CoV-2– specific immunity correlate with disease severity. METHODS. In this study, SARS-CoV-2–specific T cells and antibodies were characterized in uninfected controls and patients with different coronavirus disease 2019 (COVID-19) disease severity. SARS-CoV-2–specific T cells were flow cytometrically quantified after stimulation with SARS-CoV-2 peptide pools and analyzed for expression of cytokines (IFN-γ, IL-2, and TNF-α) and markers for activation, proliferation, and functional anergy. SARS-CoV-2–specific IgG and IgA antibodies were quantified using ELISA. Moreover, global characteristics of lymphocyte subpopulations were compared between patient groups and uninfected controls. RESULTS. Despite severe lymphopenia affecting all major lymphocyte subpopulations, patients with severe disease mounted significantly higher levels of SARS-CoV-2–specific T cells as compared with convalescent individuals. SARS-CoV-2–specific CD4+ T cells dominated over CD8+ T cells and closely correlated with the number of plasmablasts and SARS-CoV-2–specific IgA and IgG levels. Unlike in convalescent patients, SARS-CoV-2–specific T cells in patients with severe disease showed marked alterations in phenotypical and functional properties, which also extended to CD4+ and CD8+ T cells in general. CONCLUSION. Given the strong induction of specific immunity to control viral replication in patients with severe disease, the functionally altered characteristics may result from the need for contraction of specific and general immunity to counteract excessive immunopathology in the lung. FUNDING. The study was supported by institutional funds to MS and in part by grants of Saarland University, the State of Saarland, and the Rolf M. Schwiete Stiftung

High levels of SARS-CoV-2 specific T-cells with restricted functionality in patients with severe course of COVID-19

Patients infected with SARS-CoV-2 differ in the severity of disease. In this study, SARS-CoV-2 specific T-cells and antibodies were characterized in patients with different COVID-19 related disease severity. Despite severe lymphopenia affecting all major lymphocyte subpopulations, patients with severe disease mounted significantly higher levels of SARS-CoV-2 specific T-cells as compared to convalescent individuals. SARS-CoV-2 specific CD4 T-cells dominated over CD8 T-cells and closely correlated with the number of plasmablasts and SARS-CoV-2 specific IgA- and IgG-levels. Unlike in convalescents, SARS-CoV-2 specific T-cells in patients with severe disease showed marked alterations in phenotypical and functional properties, which also extended to CD4 and CD8 T-cells in general. Given the strong induction of specific immunity to control viral replication in patients with severe disease, the functionally altered phenotype may result from the need for contraction of specific and general immunity to counteract excessive immunopathology in the lung

Replication Data for: Unfair fights: Power asymmetry, nascent nuclear capability, and preventive conflict

Scholars have long recognized that imminent shifts in relative power may motivate declining states to initiate conflict. But what conditions exacerbate the risk posed by these anticipated power shifts? Building upon existing bargaining models of war, I show that larger initial power asymmetries increase the probability of preventive conflict. Theoretical extensions that account for certainty effects and variable costs of war, both of which are linked to initial dyadic power balances, drive this relationship. It follows that looming power transitions in which rising states approach and surpass parity, long considered war-prone scenarios, are not particularly problematic. Instead, the risk of conflict is greatest when preponderant powers confront conventionally weak but rising states. I test the theoretical predictions in the context of anticipated power shifts due to rivals pursuing nuclear weapons. Extensive empirical tests that relax assumptions employed in prior analyses of preventive conflict offer strong support for this contention. These results shed light on the underpinnings of many pressing contemporary interstate security issues

Certainty and War

Does greater certainty about an adversary’s attributes cause peace? What states believe they can secure through force dictates the diplomatic settlements they will accept. In prevailing accounts which preclude assessment errors, certainty promotes peace as states can readily identify agreements preferable to war. Yet, empirically, high-certainty assessments often contribute to bargaining failure, rather than success. This dissertation resolves the tension. Assessments are not objectively given; leaders must form them through subjective processes. Consistent with behavioral studies, leaders are often more certain than available information warrants. Incorporating these overprecision errors, I show certainty can increase the risk of war. Hence, the relationship between certainty and war is conditional. Whether estimates are overprecise depends on the information leaders receive from advisers who have specialized expertise due to a division of labor. Failure to tap into this expertise generates overprecise estimates. This is particularly likely when leaders fail to gather information pertinent to an adversary’s political (versus military) attributes by marginalizing a state’s diplomats—such as US State Department officials. Bureaucracies affect state behavior through the substantive expertise they provide, not through parochial preference divergences which dissipate during crises. To test the argument I construct a measure of certainty using an original corpus of declassified security documents from US Cold War crises. Quantitative tests using the measure demonstrate that State Department officials provide assessments with less certainty than counterparts and the relationship between certainty and conflict is conditional on the State Department’s role. When State Department officials are heavily involved, certainty leads to peace; when marginalized, certainty is likely due to overprecision and leads to war. Case studies of the Bay of Pigs and Iraq War assess implications that elude quantitative testing. Presidents marginalized diplomats, privileging CIA estimates in 1961 and Pentagon estimates in 2003. Each agency offered high-certainty estimates over political attributes affecting conflict outcomes: popular uprisings in Cuba and stability in post-Saddam Iraq. Overprecision is not a matter of hindsight as marginalized advisers invoked greater uncertainty before hostilities commenced. Integrating behavioralist and rationalist approaches offers greater explanatory power in quantitative tests and provides insights into historical cases that are puzzling for extant theories. Moreover, the dissertation shows that certainty is not strictly welfare enhancing and flags policy conditions conducive to assessment errors and costly foreign policy blunders.Governmen

Replication Data for: Certainty and War

This dissertation explains why a leader's certainty about adversary attributes sometimes causes peace (as conventional wisdom suggests) and sometimes causes war. Certainty facilitates bargaining and peace when the available information is sufficient to justify that certainty, as in standard rationalist accounts. However, leaders are frequently more certain than the available information warrants. These errors of overprecision can increase bargaining demands and consequently the probability of conflict. Whether leaders make overprecision errors depends on the information they solicit from senior advisers, particularly whether they collect information from those advisers with a substantive focus on adversary political, as opposed to military, attributes. I test and find support for the theory using a new measure of foreign policy elites' estimative certainty based on declassified security documents from international crises. Case studies on the Bay of Pigs and Iraq War further illustrate the logic and rule out alternative hypotheses

Replication Data for: Mutual Optimism as a Cause of Conflict: Secret Alliances and Conflict Onset

A prominent international-relations theory posits that mutual optimism, due to two sides holding divergent estimates of their relative bargaining power, causes interstate conflict. We develop a theory of mutual optimism in which conflicting bargaining power estimates arise from asymmetric information about which, if any, third parties will join either side in a military dispute. We contend that secret alliances can generate mutual optimism, which increases the probability of conflict. By exploiting secret alliances as a measurable source of private information, we provide the first systematic test of mutual optimism that directly assesses a state's secret capabilities. Optimism exists when a state's secret allies are more numerous or powerful than anticipated by opponents. Our empirical tests—as well as robustness checks—strongly support our theoretical expectation. We conclude that mutual optimism is an empirically, as well as theoretically, important cause of interstate conflict

Replication Data for: How Uncertainty about War Outcomes Affects War Onset

In canonical accounts of war, conflict outcomes are inherently uncertain. Contesting literatures posit that this uncertainty, arising from stochastic elements of the war-fighting process, may induce conflict due to greater risks of miscalculation or foster peace by breeding caution. We theorize that states, on average, exhibit prudence when confronting greater uncertainty. Despite its conceptual importance, extant proxies for uncertainty at various levels of analysis—such as polarity, balance of power, system concentration, and dyadic relative capabilities—are imprecise and theoretically inappropriate indicators. To overcome this shortcoming, we theorize the conditions that elevate the magnitude of uncertainty over conflict outcomes and introduce a novel measure that captures this uncertainty within any k-state system. Through extensive empirical analysis, we confirm uncertainty’s pacifying effect and show how this effect operates at different levels of analysis

Mutual Optimism as a Cause of Conflict: Secret Alliances and Conflict Onset

A prominent theory in International Relations posits that mutual optimism, due to two sides holding divergent estimates of their relative bargaining power, causes interstate conflict. This paper develops a theory of mutual optimism in which conflicting bargaining power estimates arise from asymmetric information about which, if any, third parties will join either side in a military dispute. We contend that secret alliances can generate mutual optimism which increases the probability of conflict. By exploiting secret alliances as a measurable source of private information, we provide the first systematic test of mutual optimism that directly assesses a state’s secret capabilities. Optimism is present when a state’s secret allies are more numerous or powerful than anticipated by opponents. Our empirical tests and numerous robustness checks strongly support the theoretical expectation. We conclude that mutual optimism is an empirically, as well as theoretically, important cause of interstate conflict.Governmen

Mutual Optimism as a Cause of Conflict: Secret Alliances and Conflict Onset

A prominent international-relations theory posits that mutual optimism, due to two sides holding divergent estimates of their relative bargaining power, causes interstate conflict. We develop a theory of mutual optimism in which conflicting bargaining power estimates arise from asymmetric information about which, if any, third parties will join either side in a military dispute. We contend that secret alliances can generate mutual optimism, which increases the probability of conflict. By exploiting secret alliances as a measurable source of private information, we provide the first systematic test of mutual optimism that directly assesses a state's secret capabilities. Optimism exists when a state's secret allies are more numerous or powerful than anticipated by opponents. Our empirical tests—as well as robustness checks—strongly support our theoretical expectation. We conclude that mutual optimism is an empirically, as well as theoretically, important cause of interstate conflict