Cruz's father didn't become naturalized until 2005, and until 2014 Cruz was a dual citizen of Canada, and, according to a friend of his, knew he was a dual citizen long before the media broke the news to him in 2014.
Whatever the case, the amount of time you live in the US doesn't determine if you are a "natural born citizen."
The sole purpose of the NBC requirements is to prevent a foreigner from becoming president.
Which the founding fathers would have recognized him as being.
He had the ability to get Canadian citizenship but he never asserted that citizenship. By your definition Donald Trump is never renounce his British citizenship which he is equally entitled to as cruise through his mother.