But Mitt's still a nickname. As you also stated above, his father's cousin Mitt was actually named Milton.
AFAIK, Mitt is an actual middle name. According to all sources, his full name is "Willard Mitt Romney", not "Wlllard Milton Romney" or anything like this. So he uses his middle name. Big deal.
Right, I understand that. I was trying to clarify (and did an exceptionally poor job, in hindsight) that if his name was "Willard Robbie Romney" and he went by Robbie (God forbid), the name Robbie itself is still intrinsically a nickname regardless of its presence on his official birth certificate. Or it is in my opinion; I suppose some may disagree with that.
But of course, this is a complete non-issue.