Marshall Sylver is about as "mainstream" as stage hypnotists get in North America. He never got close to the mass-market media saturation Paul McKenna enjoys in England, but he had a successful stage show at Planet Hollywood in Las Vegas for years, he had a late-night infomercial that ran for a couple of years in the 1990s, and, perhaps most notably, he had a memorable appearance on LATE SHOW WITH DAVID LETTERMAN, leaving stage manager Biff Henderson with a problematic post-hypnotic suggestion that knocked him out cold:

http://www.youtube.com/watch?v=p8ZBssi_Oqg

He's not to be confused with Tom Silver, the other semi-mainstream stage hypnotist who guests on various TV shows (no relation as far as I'm aware).

Ronald Reagan, on the other hand, was a gifted public speaker whose charismatic, Hollywood-honed personality and friendly approach resonated with conservative voters.