Abstract What is the impact of a crisis on the belief systems of leaders? We know from a substantial body of research that the beliefs of leaders impact their decision making processes. These beliefs are generally assumed to be stable, which makes them a reliable tool for explaining decision making behavior. There is, however, some limited evidence that suggests that when crises are experienced by leaders as a traumatic event, their beliefs can be affected. This article studies the potential impact of crisis‐induced trauma on leaders' belief systems by measuring the operational codes of Dutch Prime Minister Mark Rutte before and after the shooting down of flight MH17 in 2014 in Ukraine. We use quantitative content analysis of written texts such as the speeches by Rutte. Our aim is to contribute to the crisis management literature that focuses on individual leadership and crises by finding out whether Rutte's operational code changed significantly after the downing of flight MH17. We conclude that there were two significant changes in Rutte's belief system, but these cannot be attributed to the effects of the traumatic event only. Therefore we offer an alternative explanation that combines the traumatic event hypothesis with the crisis‐learning hypothesis.