There is also a strong link to modern UFO events such as the famous 1980 RAF Bentwaters Rendlesham incident (UK's version of Roswell - the base was long known as a secret US European outpost with nuclear weapons). Numerous military staff have come forward over the last decade confessing that yes, UFOs have deactivated and even destroyed nuclear weapons and that UFOs are attracted to bases containing nukes.
Many consider this to be the central and likely reason for secrecy on the UFO subject - that our most powerful and destructive weapons can be deactivated by a force more powerful than ourselves. This theory ultimately renders mankind and the governments there to protect them, powerless. Of course no government would say publicly that UFOs have deactivated their nukes, any admission to this would be a confession that they ultimately have no way to protect their citizens. Of course, there is an additional national security concern which is that a functional nuclear missile base is an essential strategic deterrent against rogue nations.
This is further discussed on Coast to Coast AM :
I recommend you listen to this entire feature over the weekend:
He said he's had contact with over 100 military employees who knew of UFO activity that occurred when they worked at various facilities between 1964 and 1996. There was an incident at Malmstrom AFB in March 1967 where a large red disc-shaped object was seen over the missile area, and all 10 missiles simultaneously went offline.
The guidance and control systems were affected, and the hardware had to be replaced, he detailed. This technological display of shutting off the missiles seemed to be sending a message or "wagging a finger," he commented. Conversely, missiles suddenly went into launch mode at Minot AFB when a bright object was seen over the launch site. A similar episode in Soviet Ukraine occurred in October 1982, when missiles were suddenly activated at an ICBM base while a saucer-shaped object was observed nearby.
A 1964 test of a nuclear missile sent across the Pacific Ocean was said to be thwarted in progress by a UFO, and the incident was purportedly captured on film.
For more, see Hasting's 'Big Sur' report (PDF file).