It would take a serious manic, to fire a nuke, even a team of maniacs.
Firstly, firing a nuke against anyone, would ensure you would lose becuase an attack of that magnatude with so many other countries equiped with the same firepower would effectively ensure the end of your country.
Countries like nukes becuase they are a show of military strength and prowess, and provide protection against other nukes that wont be fire. They are really only there for the "fear factor"
Would you open fire with cruise missiles on a country if you knew they could nuke you into oblivion? i think not.
As for a dictator saying fire a nuke at America, i bet many of the capable technitians wouldnt have the balls of steel to take so many lives, unless they were all seriously stupid and maniacal.