There appears to be a strong correlation between territorial losses inflicted on the Islamic State by an international coalition and the group’s increasingly global campaign of terrorism. Two reasons likely explain why the group is shifting toward international terrorism. The first is a top-down decision by Islamic State leaders to prioritize international attack plotting as a strategy to safeguard their self-declared caliphate. The second is a bottom-up dynamic in which foreign fighters and satellite groups are retaliating on their own initiative on behalf of the caliphate, a function of the group’s fluid command and control structures. As the Islamic State continues to lose ground, the international community should brace for a surge in international terror.