If illegals aren't subject to the jurisdiction of the U.S., then we can't arrest, prosecute, and imprison them for committing crimes in the U.S.
So they aren’t ‘subject to the jurisdiction thereof’ until they are caught. Otherwise they are not even known to be in the country.
If the Mexican Embassy has to be notified when one of its nationals is arrested in the USA, then that is prima facie evidence that the person is not fully “subject to the jurisdiction thereof”.
You are quite correct, but a lot of people around here won’t want to hear it.
“Subject to the jurisdiction thereof” is a common law concept familiar to all attorneys at the time. It included everybody except those with what we now call diplomatic immunity and members of invading armed forces.
It is exceedingly unlikely those who wrote or ratified 14A intended to include children of illegal immigrants, however. This is largely because at the time there WERE no illegal immigrants.
The first federal restrictions on immigration were passed in 1882. So in 1868 there were no illegal immigrants.
All persons within the United States are obligated to obey the law, yet not all persons within the United States owe political allegiance to the United States.
Sen. Lyman Trumbull, Framer of the 14th Amendment said:
“The provision is, that ‘all persons born in the United States, and subject to the jurisdiction thereof, are citizens.’ That means ‘subject to the complete jurisdiction thereof.’ What do we mean by ‘complete jurisdiction thereof?’ Not owing allegiance to anybody else. That is what it means.”
This admits that a person born in the United States might not be subject to the jurisdiction of the United States, they might owe allegiance to somebody else.
If birth within the United States was the sole requirement for citizenship there would be no jurisdiction proviso in the 14th Amendment.
Foreigners owe allegiance to their country as do their children.