"I started ranting about getting a Wall about 4 years before Sharon on this very site. It seemed just so well, obvious. There was NO other way out of the box. And so it goes."
The first to have the idea...maybe when you posted about it -perhaps it got back to Sharon.
Prime Minister Sharon was a late adopter of separation. It really became a national discussion when Ehud Barak adopted it in his waning days in office. His famous fall, 2000 "Us over here, them over there" speech (which much of the left called racist) was the real beginning, though some (like Uzi Dayan) were talking about the idea even earlier.