This research brief describes results of our experimental and correlational studies conducted between 2011 and 2019 on how weak personal ideals, high self-esteem, and uncertain circumstances combine to cause states conducive to aggressive religious radicalization. Despite theoretical speculation about the importance of these variables since the middle of last century, only scattered empirical research has investigated how combinations (of two) of them affect religious radicalization. The present research is the first to investigate all three variables simultaneously. Past research has typically found that experimentally manipulated uncertainty threats cause moral rigidity and extremism, especially among people with high self-esteem (reviewed in Jonas et al., 2014). We went beyond this past research by assessing weak ideals as an additional vulnerability to radicalization. In most of the studies summarized here, we assessed participants’ self-esteem and the extent to which their lives were guided by personal ideals. We then randomly assigned them to experience either uncertainty-related threatening or less threatening conditions. We expected those with weak ideals and high self-esteem in the threatening conditions to be especially extreme and belligerent about their religious convictions and related moral stances. Our premise was that where strong personal ideals are absent, radical ideals should be more able to take root. To the extent that strong personal ideals are necessary buffers against the appeal of radicalization, policy efforts to decrease radicalization that focus mostly on encouraging people to focus on practical and secular inducements will miss the mark.