Yes, Cecil covered this a decade or so ago:
Not so. I was born just as you describe, and still hold multiple passports with the full knowledge of the authorities. From the US State Department (bolding mine):
I held all my nationalities automatically at birth, and will continue to do so until such time as I choose to relinquish them.
Dead Badger, thank you for explaining this and fighting my ignorance. Over the years I had heard conflicting reports of dual citizenship being illegal for US citizens but also heard of some people who did have dual citizenship. I never bothered to pursue the matter but, thanks to you, think I understand it now.
What would happen if the country to which the US wanted to deport someone they had stripped of citizenship no longer existed? Would they send them back to the same geographical area, no matter the political status?