The SAR has members descended from Frenchmen who came over to fight in the Revolution. I don't know if his Robinette ancestor was one of those Frenchmen but I think I once saw something showing that he has Revolutionary War ancestry--neither Irish nor French.
Maybe Henry Louis Gates can feature Biden on "Finding Your Roots."
There was a Fort Robinette in the Corinth, Mississippi, area that figured in the Civil War fighting there but I don't know if its namesake had any relationship to the current incumbent of the White House.
And I'm one them, my French ancestor was in a Virginia Militia Company from the backwoods and was an interpreter between French and America troops at Yorktown. Also had six other ancestors in the Revolutionary War, with one who fought for the British and when captured in 1777 decided to stay in America.