The idea of mutually assured destruction was a result of political and military tensions between the US and USSR. Both of these countries built up military technologies that were capable of killing millions of citizens in just a few minutes. Both countries wanted to be able to inflict a severe amount of damage on the other in case of an attack.
This is why the phenomenon of mutually assured destruction was created, as neither country wanted to unprepared if war was to break out between these two countries.
The Senate tradition of unlimited debate has allowed for the use of the filibuster, a loosely defined term for action designed to prolong debate and delay or prevent a vote on a bill, resolution, amendment, or other debatable question.