I think everyone having nukes is more like all my neighbors having truck bombs parked in their driveways. Even if they're just for deterrence against other people who might use truck bombs, I'm screwed if one of them goes off for any reason. Guns don't really compare.
Well, this is true. Of course, The owners of those bombs would be screwed, too. And they know it. That's why, if they have half a brain, they've hired people to keep those bombs safe. And those people know that keeping those bombs from going off accidentally is a very important part of that job.
Edit: Fuck! I can only find 3 and 4! is 4 stand-alone, or would I be completely confused?