Hindsight
by Harry Turtledove
When 1950’s science fiction writer Mark Gordian has a flurry of great stories
(“Watergate,” “Houston, We've Got a Problem,” “Neutron Star,” and the
ultimate time-travel yarn, “All You Zombies”), Pete Lundquist has nothing but
admiration, until Gordian comes out with a story that Pete himself has been outlining.
“Oh, my God! Tet Offensive!” McGregor stared from one of them to the other.
“You’re not telling me that one’s based on fact?”
“Hindsight” by Harry Turtledove, in Analog,
mid-Dec 1984.