All *civilized* countries have a mechanism by which a person can formally,legally,renounce his/her citizenship if they wish.Canada would surely have such a law.If Ted Cruz wants to be president he'd be wise to renounce his Canadian citizenship...not because there's anything wrong with Canada...but because some might fear,with or without justification,that his loyalties as President might be clouded in certain situations (like when Congress declares war on Canada).
RE: If Ted Cruz wants to be president he’d be wise to renounce his Canadian citizenship...
If he is a DUAL CITIZEN by birth, that probably disqualifies him from the presidency based on Section 1 of Article Two of the United States Constitution.