Human: What is the Dead Hand? Assistant: 
The Dead Hand is a system that was created by the Soviet Union to ensure that nuclear retaliation, and hence deterrence, remained possible even if its leadership were to be destroyed in a surprise attack. In contrast, Thompson argues that Perimeter's function was to limit acts of misjudgment by political or military leadership in the tight decision-making window between SLBM/cruise missile launches and impact. He quotes Zheleznyakov on the purpose of Perimeter being "to cool down all these hotheads and extremists.