How can the President of the US, and one who swears allegiance to the US such as a military service possibly also bear allegiance to another country??
Also, I don’t know about now, but a few years past,when a naturalized citizen took his/her oath of allegiance had to disclaim allegiance to any other country. There is a name for that denial but I just don’t recall it.
The feds used to treat acquiring foreign citizenship as a renunciation of US citizenship. It was the USSC that changed that in the ‘60s.