“The thing is, all experts agree that he was naturally born in Canada,” Paul said on CBS’s “Face the Nation.” “And so the question is — can you be naturally born in Canada and also be considered to be a natural born citizen? It hasn’t been decided.”

“[The Founding Fathers] used this unusual language in the Constitution of ‘natural born’, and so I think it will be brought up,” the Kentucky Republican continued. “Congressman [Alan] Grayson from Florida is already saying he’s going to challenge it in court. I think the Democrats will challenge it at the very least and I think it will have to be decided by the Supreme Court.”

Cruz, the GOP front-runner in Iowa, was born in Canada to an American mother and Cuban father.