Normally heard in the context of `mutually assured destruction`; when something is mutually assured, it is guaranteed to happen to both parties involved. This phrase is normally linked to discussions involving nuclear weapons, where `mutually assured destruction` means that we are all guaranteed to die.
Hindsight is always 20-20
But looking back it's still a bit fuzzy
Speak of mutually assured destruction?
Nice story...tell it to Reader's Digest!
- Megadeth, _Sweating Bullets_