If Cruz was born in 1930 he would not be a US citizen. He’d be all Canuckistan. A law had to be created to create Cruzie a US citizen. No US law no US citizenship. Fed statutes are not natural.
Every US citizenship is conveyed by law, including natural born citizenship. Otherwise Indians and slaves would have been natural born citizens by virtue of where they were born. It took a Constitutional amendment to fix the slavery citizenship issue.