Nolan, William F. "The Worlds of Monty Wilson"
Divergence: 1968 CE
Summary: In 1990, a NASA employee suddenly "shifts" to a timeline where Sirhan Sirhan missed Robert Kennedy and Apollo 11 met disaster.
Published: In Amazing Stories, July 1971; Alien Horizons, Pocket 1974 (0671779281); and 100 Great Science Fiction Short Short Storie (eds. Isaac Asimov, Martin H. Greenberg and Joseph D. Olander), Doubleday 1978 (0385130449) and Avon 1978 (0380507730).