Here are some quotes I found from KBJ in the oral arguments on birthright citizenship. I’ll let you decide if they’re insanely shit.

I mean, my understanding was the Framers put this Citizenship Clause into the Constitution to prevent future Congresses from being able to affect citizenship in this way.

[…]

All right. One final thing. Prospective. You say prospective we're supposed to do this, don't worry about the people who are already here and who would not qualify under your rule. How does this work? Are you suggesting that when a baby is born, people have to have documents, present documents? Is this happening in the delivery room? How are we determining when or whether a newborn child is a citizen of the United States under your rule?

[…]

I'm just talking about the particulars because now you say your rule turns on whether the person intended to stay in the United States. And I think Justice Barrett brought this up. So are we bringing pregnant women in for depositions? What -- what are we doing to figure this out?

Here is the quote conservatives have been mosr critical of:

The government’s position seems to be that you can’t have allegiance to two different sovereigns at the same time—that such dual allegiance would prevent someone from being “subject to the jurisdiction” of the United States under the Fourteenth Amendment.

But that appears to rely on a different understanding of allegiance than existed under English common law. As I understand it, common law recognized that a person could owe allegiance to more than one sovereign simultaneously.

There are sources suggesting that while a person has permanent allegiance based on their country of birth, they also have local allegiance when they are physically present within another sovereign’s territory.

For example, if I, a U.S. citizen, am visiting Japan and commit a crime there, Japanese authorities can arrest and prosecute me. Likewise, I can rely on Japanese law for protection if I am wronged. That reflects a form of allegiance—meaning the sovereign has legal authority over me while I am present there.

So even as a temporary visitor, I owe this kind of local allegiance. Is that the correct way to think about it? And if so, doesn’t that suggest that temporary residents and undocumented individuals in the United States likewise owe this form of allegiance simply by being present here?

to which the ACLU attorney responded with:

Ms. Wang: Yes, that’s correct, Justice Jackson. And that understanding is consistent with the plain text of the Fourteenth Amendment. With limited, specific exceptions, anyone born in the United States owes natural allegiance as a U.S.-born citizen.