The Soviet Union took steps 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. No matter what was going to happen, there still would be revenge."