The Cold War profoundly affected the fate of many states; Iran and Afghanistan were two which particularly felt its effects. Their domestic and foreign-policy settings were influenced by the onset of the Cold War in ways that produced contrasting outcomes for the two countries, helping eventually to open space for the rise of radical Islamism in their politics, with impacts well beyond their boundaries. The Iranian revolution of 1978/79 resulted in the overthrow of the US-backed regime of Mohammed Reza Shah Pahlavi and its replacement with the anti-US Islamic government of Ayatollah Ruhollah Khomeini. In contrast, the Soviet invasion of Afghanistan in late December 1979 followed the seizure of power in Kabul by a cluster of pro-Soviet Communists twenty months earlier. However, both events were considerably grounded in the US–Soviet Cold War rivalry. Similarly, political Islam, or Islamism, which had a major effect on the Muslim world and its relations with the United States and its allies in the wake of the Iranian revolution and Soviet invasion of Afghanistan, arose in interaction with the dynamics of the Cold War, although it was also embedded in older schools of thinking amongst Muslim scholars. Arguably, if it had not been for the US policy of containment of the Soviet Union and the Soviet responses to it, Iran might not have moved so clearly into the American orbit and Afghanistan might not have fallen under Soviet influence. By the same token, the grounds might not have emerged in the late 1970s for the radical forces of political Islam to become increasingly assertive in their quest to redefine Muslim politics, with an anti-US posture.