The rise of "strongman leadership" across the globe, including in Western societies, has been noted in both the mass media and academic publications. Also noted is the tendency for strongman leadership to be associated with antiglobalization, anti-international institutions, and antiuniversal human rights. But less attention has been given to the tendency for strongman leadership to nurture and accelerate mutual radicalization, the process through which groups and nations drive each other to extremes (Moghaddam, 2018). This comes about in large part because strongman leaders are categorical thinkers, authoritarian, and ethnocentric: They not only perceive the world as strictly divided into "us versus them," but they also mobilize supporters through the rhetoric of ingroup superiority and aggression against "others." Depending on the context, these others can be Mexicans, Muslims, Blacks, Jews, or other minorities. What all these minorities have in common is that they are dissimilar to "our group."The mobilization achieved by the strongman is through pathological hatred: We will do whatever it takes to reject and harm you, even if we suffer in the process. Whatever the cost to us, your pain is our gain. The inevitable result of behavior driven by pathological hatred is the growth of different types of conflict. For example, inside countries the persecution of minorities instigated by the strongman leads to increased intergroup conflicts, such as of the kind we are witnessing between Hindus and Muslims in India, White nationalists and Indigenous people in Brazil, Turkish nationalists and Kurds in Turkey, and Shiites and Sunnis in Syria. Rather than trying to transform and minimize such conflicts, the strongman feeds hatreds and uses conflicts to mobilize his authoritarian base and further move the country along a path of mutual radicalization.Mutual radicalization through strongman leadership also results in heightened conflict between nations, as in the case of Iran and the United States. The strongman leadership in both Iran and the United States mobilizes their base through this conflict and also distracts from their internal problems. In Iran, the leadership keeps up a drumbeat of "Death to America" as a way to blame external factors for the terrible plight of Iranians and to justify the continuation of a corrupt dictatorship with a religious front. In the United States, the Trump administration finds Iran a useful distraction from the impeachment of the president, the cutting of food stamps and other support for the poor, and tax policies that transfer more wealth to the rich.In societies characterized by mutual radicalization, people arrive at a balkanized position where they feel "we can no longer talk to the other side," "the gap between us is too far to bridge," "there is no longer a middle way." Each side sees the other side as radical, irrational, incapable of reasoning and compromising. Each side asks, "How can they believe those things? How can they think like that? How can they deny the obvious facts?...