And what happens when such a minor child reaches the age of eighteen, does nothing to affirm US citizenship, attends university in the United States on foreign aid, and travels on a foreign passport, from a nation that did not permit dual citizenship?
Nothing happens. There is no need to "affirm US citizenship." The US government doesn't care if you hold citizenship in another country and use that country's passport, as long as you use your US passport when traveling to and from the US. Using foreign funds to attend college is not a crime, or we'd have to lock up all those Rhodes and Marshall scholars.
Why he can become the best President money can buy! Isn’t the New America just Grand!
“And what happens when such a minor child reaches the age of eighteen, does nothing to affirm US citizenship”
Did you have to affirm US citizenship at 18?
If you are born a citizen, there is nothing you need do subsequently to retain said citizenship.