[walrus01]

This is a logical and normal term in strategic military planning, the concept of knowing that your own important thing will almost assuredly be destroyed in a retaliatory strike, should you be the one to initiate the war. See also the last 70 years of cold war era mutually assured destruction calculus.

This is one of the reasons why highly advanced anti ballistic missile systems are seen as very dangerous because they upset the parity of two nuclear ICBM armed states being in approximate equal capability with each other.

The cold war never really ended.