A quote from Wikipedia to send shivers down your spine.
Journalist Ron Rosenbaum has pointed out that the operational plan for nuclear strike orders is entirely concerned with the identity of the commanding officer and the authenticity of the order, and there are no safeguards to verify that the person issuing the order is actually sane.[10] Notably, Major Harold Hering was discharged from the Air Force for asking the question "How can I know that an order I receive to launch my missiles came from a sane president?"[11]