This exact same question was raised with John McCain back in 2008, because he was born in the Panama Canal Zone: http://www.politifact.com/truth-o-meter/article/2008/may/12/...

Was that because of his race too?

I suspect we stopped hearing about McCain, and kept hearing about Obama, because Obama became president.

Like I said, a generous suspicion. I can also suspect that had McCain been elected he would not have been dogged with insinuations about his citizenship, forced to proffer his birth certificate, referred to as a "Panamanian" by his detractors, etc. etc. for practically the duration of his first term.

I agree that many racists are in the birther camp. I guess my point was that it wasn't only racists doing it.