[JPhillips]

I swear, you purposefully misstate how dual citizenship works just to torment me.

There's no record in the US of who has citizenship from other countries and no good way to go about getting that information. Then, there's no way for a person in country X to go about renouncing citizenship of country Y. They'd have to go back to the other country and even then it isn't always possible.

Basically everyone that was born on foreign soil or has a foreign national parent has dual citizenship and it makes no difference to the resident country.