Ah, its a 1920’s style Harrison.
While Gore Vidal is not a president (though he did run for Congress a few times), he was a stepbrother-in-law (sort of) to JFK and is a distant cousin of Al Gore. (Vidal’s grandfather, Thomas Pryor Gore, was a longtime senator from OK [most famous in his own time for his blindness]).
*Complicated relationship: Vidal’s mother, Nina Gore, divorced his father and married multimillionaire Hugh Auchincloss with whom she had two children. Later the couple divorced and Auchincloss married Janet Lee, who brought with her two children from her first marriage, Jackie & Lee Bouvier. Vidal’s half-siblings were the stepsiblings of Jackie Kennedy which sorta kinda makes them steprelatives.
Wow. This shit is pretty bizarre. I wish the people who did GorillaMan’s page had been more thorough and explained who FDR was related to in which way.
Ninth cousins twice removed.
No, it’s a 1920s style Coolidge! 
FDR was TR’s fifth cousin through their paternal ancestries, but was also TR’s nephew by marriage, Eleanor having been the daughter of TR’s deceased brother.