There are two important studies in the literature that examined the effects of multiple intervention types, rather than solely focusing on a single intervention type. In their path-breaking article, Regan and Aydin (2006) investigate the role of external interventions on the duration of civil conflicts. The authors argue that the effect of structural interventions–military and economic–
can be assessed better once diplomatic interventions are also integrated in the analysis. They posit that structural interventions influence the power distribution between disputants by supplying a greater incentive to fight and thus increase the conflict duration. On the other hand, diplomatic interventions shorten the length of conflict by conveying private information about the capabilities of belligerents. A better analysis, according to the authors, is therefore possible only when diplomatic interventions are incorporated into the analysis. Undertaking a cross-sectional testing, they partially find support for their argument in a way that the effect of economic interventions renders statistically significant–otherwise insignificant–if a variable for diplomatic interventions is plugged in the model. The coefficient for the military interventions however remains insignificant even after introducing diplomatic intervention variable into the model. Based on these finding, the authors eventually conclude that controlling for diplomatic intervention is crucially important in understanding the effect of external interventions in civil wars.
Regan and Aydin’s study is an important research about the role of interventions in civil conflicts. Conceptually, it is the first in the field to include multiple intervention types into the analysis. The results confirm that the findings about the impact of each intervention type might change substantially when the role of diplomatic interventions is included. Methodologically, the authors incorporate a variety of time variables through which one can assess somewhat the right
linear forms of time covariates for diplomatic interventions, and find results supporting their expectations about the inverted-U relationship between the timing of a diplomatic intervention and the duration of a civil war.
Nevertheless, there are certain gaps in their analysis to highlight. First, the direction of intervention is not specified in any of their models. There are numerous debates in the literature explaining the differential effects of biased interventions based on the side the treatment is targeted. Second, GDP is used in their analysis as a proxy for country’s general capacity. Yet it is a disputable measure for such specific purpose, and the literature suggests more representative measures, including, amongst many others, GDP per capita and composite index of national capacity from COW project. Finally, the article clearly reveals the need to include different intervention types into the analysis. However, the theoretical framework they are proposing basically predicts the effect of diplomacy on conflict duration and the impact of mediations on other intervention types. Thus, they do not necessarily provide a comprehensive theoretical framework in which multiple intervention types can be incorporated and tested for their overall effects.5
In another important study, Lektzian and Regan (2016) investigate the role of economic sanctions and military interventions on conflict duration. Emphasizing the inability of standalone sanctions as an effective tool to foster peace in a civil conflict, the authors argue that sanctions can decrease the duration of conflicts only if complemented by military interventions as an enforcement tool. Testing their hypothesis in statistical models, they find support for their claims.
5 I will continue discussing more about Regan and Aydin (2006) article in the chapter on interdependence.
Lektzian and Regan’s article is important especially demonstrating the ability of synergetic effects of foreign interventions on civil wars and also the need to study interventions by integrating multiple types together. However, there are a couple points that the article needs to address. First, temporal difference between economic sanctions and military interventions in a given conflict is not considered. That is, the authors disregard the interval between a sanction and a military intervention in a given conflict, and only focus on the presence of such external involvements irrespective of their performed times. However, the effect of each intervention type naturally has influence on a conflict for only some certain time period, and then the impact could naturally peter out over time. Second, the analysis does not account for the interdependence between such foreign involvements. Second, the authors do not control for the dynamics between disputant parties, such as the relative power between belligerent forces. In the literature, such features are critical to determine the duration of conflict especially in the face of external involvements.
Third, Lektzian and Regan use a country-level data as opposed to a dyadic data, which may not be the most appropriate unit of analysis to analyze the dynamics in civil conflicts where the fighting takes place between a government and a particular rebel group. A dyadic dataset including state-rebel group dyad, as compared to a country-level data, might provide with more nuanced results. A country at a given month might be conflicting with, for instance, three rebel groups at the same time. It is difficult to tease out which rebel group receives military interventions or gets targeted in such foreign involvements when a country-level dataset is used. Finally, the study focuses on only two particular intervention types without providing a more general framework to customize it for different combinations of intervention types.
Eventually, these two important articles are intuitive for the scholarship on intervention because they cast light on the need for an integrative research in studying foreign interventions in
civil wars. In both articles, the effects of particular intervention types change as an additional type is introduced into the analyses, revealing that failure to do so leads to spurious findings in regard to the impacts of these treatments. At the same time, it demonstrates that there is a need for more comprehensive theoretical frameworks in which various multiple interventions are integrated and then analyzed for their effectiveness in the context of civil wars.