Potential presidential candidate Donald Trump says he has "just a little" doubt that President Obama is U.S.-born but his feeling doesn't make him an "idiot."

The mogul and TV reality star suggested in an interview with ABC's "Good Morning America" that aired Thursday that he's reluctant to discuss the topic because "everybody that even gives any hint of being a 'birther,' a word you didn't use, even a little bit of a hint like, 'gee, maybe you know, just maybe there is this much of a chance,' they label them as an idiot."

Trump said that's not him. 

"Let me tell you, I am a really smart guy. I was a really good student at the best school in the country. The reason I have a little doubt, just a little, is because he grew up and nobody knew him. When you interview people, if I ever got the nomination if I ever decide to run, you may go back and interview people from my kindergarten. They'll remember me. Nobody ever comes forward. Nobody knows who is he until later in his life. It's very strange. The whole thing is very strange."

Obama was born in Hawaii. He lived in Indonesia from the time he was six until age 10.

As for other presidential wannabes, Trump went through a list of potential 2012 contenders, giving one-line assessments of each.