Have you seen the state of the rest of their armaments? Countries that have to bum artillery and soldiers off of North Korea are not in any position to go up against NATO.

If you're a Russian officer in charge of nuclear stockpile maintenance, why in the world wouldn't you pencil-whip the paperwork and steal the funding? If you're ever caught, it will be under circumstances where nobody will be in a position to do anything about it.

There is a good chance of this. Nukes need ongoing yearly maintenance to be operational, without that they are basically just a flying tin can. The whole movie trope of stealing an old nuke and using it doesn't apply to the real world.

Also corruption is somewhat accepted in some countries as it allows those at the top to have legitimate means of disposing of traitors when needed without that hassle of drumming up fake charges.