Here's Keith's full performance of "America" with The World's Most Dangerous Band, presented in better video and audio quality than previously uploaded by others.
My source is in mono, but I edited in the stereo audio from BetaGems Lost Media's partial performance that's uploaded here:    • Keith Emerson 9-18-86 late night TV p...  .

The stereo kicks in at 2:00; the mono returns after the performance.