This chapter documents the final collapse of detente, focusing in particular on events in the Middle East, where the Iranian Revolution, and then the Soviet invasion of Afghanistan, reshaped the regional order. The chapter argues that the superpowers' differing perceptions of what constituted their legitimate interests led to conflicts in the third world. Linkage, the belief that improved Soviet–American relations would dissuade the Soviets from exporting revolution to the third world, failed as it did not align with the Soviet self-perception as America's equal. The decline of detente is traceable to multiple factors, including the Soviet appetite for maintaining a third world clientele and the twists and turns of US domestic politics. By the time the Soviets invaded Afghanistan, detente was already on the rocks and the Soviet–American relationship continued to worsen. The vision, once entertained by the now-senile Brezhnev, of a world co-managed by the United States and USSR as equals faded, leaving in its wake an uncertain and hostile environment.