Two theoretical foci guide this inquiry. The first, that of the ephemeral gain, emerges from elements of the social psychology literature and an analysis of historical trajectories that are most likely to lead to political extremism. Three pathways are suggested to follow from the ephemeral gain: (1) the threat and fear of reversion to an earlier state of subordination, (2) perceptions of injustice leading to anger and blame, including a possible stereotyping of innocents, and (3) humiliation-shame. All three, separately or in some combination, can lead to extremist behavior. As we shall see, whereas Stalin's extremist behavior is best explained by the fear of reversion along with the humiliation and shame at earlier defeats, the rise of Nazism centers more on the sequence stemming from perceptions of injustice leading to anger, blame, and stereotyping behavior. Humiliation and shame at the German defeat ending World War I, of course, was also relevant. Illustrations of the three pathways and, where available, scientific evidence on their applicability are provided.

The second general source of extremism, mortality salience, treated in the following chapter, has received increasing prominence and arises directly from the social psychological literature. Separately, neither principal component of the theory has the explanatory power that both the ephemeral gain and mortality salience provide when taken together.

Finally, although not theoretically central because it does not explain the sui generis origins of political extremism as does the ephemeral gain combined with mortality salience, nevertheless the diffusion of extremist behaviors across national boundaries deserves mention.