Happened in 1984. From Micheal Reagan's book, "The City on A Hill," page 195. Short version, Renaldus Maximus was in his Santa Barbara home getting ready to do his weekly Saturday radio address. When asked to do a mike check, instead of doing the standard "one, two, three," he said the following:
"My fellow Americans, I am pleased to tell you today that I've signed legislation that will outlaw Russia forever. We begin bombing in five minutes."
It didn't go out on the air, but was recorded by the audio tech; but some reports say that the Soviet Union went to a higher state of readiness for a little while (since they monitor all White House communications).
Here's a link to the audio clip:
[url]http://www.archervalerie.com/ronradio.wav[/url]
[edited to change 198[b]3[/b] to 198[b]4[/b]]