We know that because jurisdiction is such a fundamental concept that it needs no further specification. It's fundamental to any system of laws, if a jurisdiction is not defined, the system of laws is useless. Running a legal system without a jurisdiction is like running computer code without memory space.

The US legal system defined everyone in its soil to be under its jurisdiction, _except diplomats_, because of diplomatoc norms.

If an illegal immigrant kills a person while in the US, they get tried according to US law. If a diplomat kills a person in the US, they do not get tried because the US has no jurisdiction over that diplomat.

> You’re saying we need to look to the international meaning of some Latin phrase (“jus soli”).

Discussion of law discussion that uses comparison with international standards is quite common in every legal system. The sentence regarding the murder of a relative of mine had citations of Italian law, German law, some Spanish doctrine. It was also peppered with Latin terms and expressions, because Roman law had quite an influence in all Western legal systems.

So yeah, sometimes discussions of law can be complicated. This one... Ain't.

Read Jackson’s opinion. The amendment was debated at the time and the history records show that at minimum it was intended to include all people living here who didn’t have permission to not follow laws like diplomats or invaders.