If you think it’s controversial as to whether Cruz was a natural born dual citizen, Canada by place of birth, and U.S. by his mother’s lineage, then you have proven the first part of it.
But, let me ask you this question: Was Cruz also a Cuban citizen?
Based on my research, Cruz would be eligible to be a Cuban citizen if his father filed application for it. I doubt that ever happened.
http://www.cubanet.org/htdocs/ref/dis/const_92_e.htm
Chapter II
Article 29c
However, your question is a good one that I haven't heard before. Does Cruz also have Cuban citizenship descended to him by his father? The timing of Rafael Cruz' Canadian citizenship has not been disclosed.
The United States naturalization oath of allegiance big with "I hereby declare, on oath, that I absolutely and entirely renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty, of whom or which I have heretofore been a subject or citizen;"
Canada's does not contain a renouncement of previous allegiance.
Did Cruz inherit Cuban citizenship via his father, American citizenship via his mother, and Canadian citizenship via the land?
Did Cruz have triple citizenship? How can one be a natural born of one country when having birthright claims from three different countries simultaneously?
Well done with that question!
-PJ