Evolutionary psychology often relies on experimental methods for testing theories due to their capacity to isolate independent variables, thereby enhancing internal validity. The scientific problem in this study, however, lies in the fact that an increase in internal validity in experiments might risk reducing ecological validity. Therefore, the purpose of the study is to test experimental results from the evolutionary coalitional psychology in a real case, to evaluate the ecological validity of the theory. The case is the Ukraine war and the method is a qualitative thematic text analysis, of President Volodymyr Zelensky's speeches, close to Russia's invasion on February 24, 2022. The results reveal that the president in his speeches, motivates with a collective gain of participating in the defence of Ukraine, exhibits a punitive attitude towards perceived free-riders, and does not show any gender bias in his appeals. The evidence of collective gain and a punitive attitude is particularly notable as it aligns precisely with the theoretical expectations based on previous experimental results from coalitional psychology. This alignment between real-world findings and experimental predictions enhances the ecological validity of the theory, thus fulfilling the aim of the study. The conclusion is that evolutionary psychology can be effectively applied to real- world conflicts within peace and conflict studies.