Cruz absolutely is a natural born citizen under the laws of the United States. That Larry Tribe article doesn't say Cruz is ineligible, it says that Cruz is an unbelievable hypocrite because the pure originalism he claims to support would arguably consider him not natural-born. Children born abroad to US parents, under the last couple of centuries of American law, are not naturalized at birth, they are US citizens from the moment of birth.

Cruz is a loathsome hypocritical sack of shit, but as we've learned to our horror, that doesn't disqualify a person from becoming president.