Our fertility rate is below or at replacement, so population increases are mainly by immigration.

1 million per year is 0.3% per annum. Hardly unsustainable.

BTW – I’m close with someone whose parents were from a “southern neighbor” that isn’t Mexico, but has a similar per-capita income. Her father was a taxi and later a truck driver, her mom became a teacher. They went back and forth, she spent about 2/3 of her childhood outside the US.

The siblings and cousins that I’ve met generally have at least a master’s — quite a few lawyers, doctors, and engineers. Don’t assume that people from a humble background won’t educate themselves.

Let’s grant MORE visas. Even manual work needs doing. Better to satisfy the demand for immigration from all social strata vs allowing criminal gangs to control it.