1) Air Force ICBM launch operations: The General in charge had a serious drinking problem (consider that for a moment), to the extent that he went on a bender in Moscow. Among launch officers, there was widespread cheating on qualification tests, disregard for regulations (such as sealing doors to secure rooms), and very low morale.
2) Air Force nuclear bomber operations: At one point, they lost track of a nuclear bomb (or maybe cruise missile), and it was flown to a base in another part of the country before anyone figured it out and could track it down. The Secretary of Defense fired the General in charge.
3) Security at facilities containing highly enriched uranium/plutonium (the essential material to making weapons; the one component that keeps terrorists from making one): At one facility, some peace protestors (not James Bond-level attackers) breached the security and setup a protest next to a building containing the materials. They were there for something like 30 minutes before they were discovered and apprehended.
4) And now this.
This isn't a system that can succeed 99.999% of the time. If one nuclear weapon gets into the hands of someone willing to lose it, millions of people will die and then you can imagine the response - the course of history and civilization will change.