Churchill was born in 1874, at that time a woman lost her US citizenship when she married a foreigner. Churchill himself recognized that he could only have become an American citizen if his father had been an American citizen.
“By the way, I cannot help reflecting that if my father had been American and my mother British instead of the other way around, I might have got here on my own. In that case this would not have been the first time you would have heard my voice. In that case I should not have needed any invitation. But if I had it is hardly likely that it would have been unanimous. So perhaps things are better as they are.” Churchill speech to joint session of U.S. Congress, December 26, 1941
By the time Cruz was born, the laws had changed. His mother did not lose her citizenship by marriage and she passed US citizenship onto her son.
OK, thanks for the information.