The Dead Zone - Season 1 Episode 13 Destiny

In the past Johnny Smith as a child and Greg Stilson, the son of a Bible salesman, briefly meet and Johnny has a future vision of danger. In the present Johnny has a vision of a restaurant graduation party tragedy and warns his employer, the father of a student. Stilson, now a Senatorial candidate being backed by Rev. Purdy, comes to town after the tragedy and Johnny gets visions of catastrophe in Stilson's wake. Johnny and Sara get together while in flashback we see how Stilson has been a total bastard all of his life, and that Johnny came out of his coma just as Stilson was sworn in as state representative. When they meet at a rally Johnny shakes Stilson's hand and sees him as the source of catastrophe - Washington D.C. devastated by a nuclear holocaust.