“So you agree that it would be up to the Supreme Court to decide the question of the eligibility of Senator Cruz to be President”
No, I assume the Supreme Court should attempt to define a Natural Born Citizen. Then the question wouldn’t be revisited with every foreign candidate that comes along. But, if the decision is not 9-0, then it becomes a political decision and the question will still not be settled.
There are many SCOTUS decision where 9 of 9 justices necessarily operate from the premise that a person born abroad is an alien, unless naturalized by Congress. You are probably unable to understand that, and so you will reword your criteria for finding that rule of law to be settled.