If he did renounce it, it would have been done because of British law. But say he didn’t have to. Let’s, for the sake of the arguement, say he became a Canadian Prime Minister. Under Canada’s law, you can be a dual-citizen and run for Prime Minister, as long as one of those citizenships is Canadian.
Could somebody born in the US, who remains a US citizen but becomes a dual citizen and becomes Prime Minister of Canada run as President if he then gives up his dual citizenship and becomes fully American?
I understand that shouldn’t happen, as intended by the Founding Fathers, but it’s the reality today.
IIRC Johnson claimed to be renouncing his citizenship because of tax issues. Under US law a person’s *worldwide* income is subject to taxation by the IRS. Very few,if any,other countries have such a policy.