During the years that his parents worked in Canada and Ted was born, you only needed an ID to go back and forth between the US and Canada. Ted did not get a passport until he was 16 and needed it to go on a class trip to England.
http://www.dallasnews.com/news/politics/headlines/20130818-ted-cruz-born-a-citizen-of-canada-under-the-countrys-immigration-rules.ece
I know, I'm trying to get a few others here to understand that very point.