Sanders, William. "Duce"
Divergence: 1940 CE
What if: Mussolini was assassinated before embroiling Italy in an invasion of Greece, and ultimately delaying the German invasion of Russia.
Summary: Nazi agents travel back in time to kill Mussolini and thereby prevent Germany's defeat by the USSR, but before doing so meet other time traveler from a different future.
Published: In Asimov's Science Fiction August 2002; and East of the Sun and West of Fort Smith, Norilana 2008 (1934648663BUY).