Key fragments are managed by which governments? And it would differ from the U.N. Security Council, how? Probably it would be Five Eyes rather than the WWII surviving super powers? But back then they were more on the same page than today, so in 10 years or 50 years, the one key to rule them all countries likely don't still get along either. I think it just devolves into an espionage race to acquire all the fragments. Or breaking the code.