If this is was the case then you would lose your citizenship ever time you left the United States for a foreign country.
*sigh*
Can you be under several jurisdictions at the same time? Of course you can. You can be under the jurisdiction of the country you are visiting AND under the jurisdiction of the United States.
Jurisdiction does not mean citizenship. Jurisdiction is one of the requirements for citizenship spelled out in the Constitution.
This is getting ridiculous.
There are good arguments for this, but those arguments have been tried at the Supreme Court (Inglis, Ark, and others) and have not convinced the majority of the Court in any case.
The easiest, quickest and most solid way to fix this is simply to amend the Constitution. Just add the phrase “and whose mother is legally a permanent resident of the United States,” to the 14th amendment.
That’s all that is needed.
Making up crap and blustering about in the insane arguments and conjectures that dominate these discussions is ridiculous.