Sgt. Pepper is Gen. Walter Bedell Smith; "The one and only Billy Shears" is the diplomat William C. Bullitt, and the "friends" include Sens. Robert Taft, Joe McCarthy and Arthur Vandenberg as well as Secretary of Defense James Forrestal and CIA Director Hoyt Vandenberg.
I wonder if this is what the Beatles actually had in mind when they cooked up the song?
Very overrated Album.