I've been thinking about this over the past few days, and the whole Canada thing could blow up into a huge issue for Cruz. Not because of the eligibility question (he's clearly eligible), but because he was a Canadian citizen until 2014, when he was 43 years old. Which raises a large number of questions: has he ever traveled with a Canadian passport? Has he ever voted in a Canadian election? Does he have property or bank accounts in Canada? Has he ever used Free Socialist Canadian healthcare? Now, none of these are disqualifying, but they do raise foreign influence and foreign preference concerns. His family moved to Texas when he was four years old, so it's likely the answer to most of these questions is no, but these are still questions that political operatives are surely looking into at this very moment.
How is he clearly eligible? He was born in Canada.