“Isn’t Leo Donofrio’s case against Obama based on the premise that he’s ineligible because his father is not a U.S. citizen?”
Yes, Obama’s father was Kenyan and a British subject at the time of Obama’s birth, which made Obama a British subject at birth.
“if that’s true, then do we need to retroactively impeach Chester Arthur, who was rumored to have been borne in Canada, and was, at birth, the son of an non-naturalized Irish immigrant father? Just curious.”
No, because Arthur was born in Vermont. And yes, his parents were Irish immigrants. However, Arthur was a citizen at the time of the signing of the Constitution,
and therefore was allowed per the Constitution to hold
the office of President. (As were our Founding Fathers.)
The Constitution states: “No person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President; neither shall any Person be eligible to that Office who shall not have attained to the Age of thirty-five Years, and been fourteen Years a Resident within the United States.”
Since Obama’s mother was a naturalized citizen (a native of Kansas) and because Obama was himself born on U.S. soil in Hawaii (a U.S. state as of 1958), why are we still having this conversation?
Well, the Roberts/Scalia/Thomas SCOTUS tossed the case. I hope this puts the matter at rest...because there are much more serious issues to discuss.