There's the usual opening citation of the 14th Amendment:
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.
The usual rejoinder notes that the children of diplomats born in the US are not considered US citizens. When asked for the law or court case that establishes this exception, I get nothing except, "Well, everybody just knows that's how it works." In other words, they just made up the exception to their made up BRC claim. One of them even linked me an article that said those children are "deemed" to not be citizens.
Deemed by who? Where is this written?
If you reject BRC, you don't have to deem anything, because the underlying argument says foreigners belong to their respective sovereign nations unless Congress legislates otherwise. That's why illegals can be deported using administrative courts rather than criminal courts: They aren't US citizens, ergo they are not entitled to the full US court system.
But I prefer to find things the Left values and set their arguments against those other values. My latest argument is:
Suppose a woman is in the US to attend college. During the course of her studies, she has a child, a son. She has no intention of her or her child becoming citizens or even dual citizens. Once her studies are concluded, she returns home with no intention of ever returning to the US. Yet, if BRC is as automatic as is argued, the child is a US citizen. Once that son grows up, he would be obligated to register for the US military selective service. Worse still, if the US engaged in military operations against the mother's country, any support, aid or comfort the child gave to the mother's country would be treason against the US.
By what justification does the US lay claim to a child that was never meant to be a US citizen, it was just born here as a matter of circumstance?