Meghan may be a duchess - for now anyway - but she is not yet a British citizen.
Zero fux given about “royals” and this loser who I thought was Canadian anyway. What do I know/Why do I care?
Yes, and even if she was she couldn’t be stripped of her American citizenship, she would have to explicitly renounce it.
It is almost impossible to take the citizenship of a natural born American. Numerous court decisions have established it as a birthright, not subject to removal by administrative action.
And frankly I wouldn’t want it any other way. Would any Freeper seriously want to give a President Sanders or a President Warren control over your citizenship?