Resnick, Laura. "A Fleeting Wisp of Glory"
Divergence: 1962 CE
What if: The Cuban missile crisis blew up.
Summary: Centuries after Armageddon, legends of the two Camelots become entwined.
Published: In Alternate Kennedys (ed. Mike Resnick). q.v.; and Galaxy #3 (May/June 1994).