Exactly. This is the comparison it feels like he's making: a universe with just the US with immigrants from a lower socioeconomic status vs a universe with j

Exactly. This is the comparison it feels like he's making: a universe with just the US with immigrants from a lower socioeconomic status vs a universe with just the US without those immigrants and then sure, the net effect is that the 'without' universe is better because if you get immigrants with relatively (vs the current inhabitants) lower education, skills, literacy, networks, cultural cohesion etc, you inevitably reduce the average person's scores on those traits, that's just simple math. And those traits correlate with social and economic well being. But the actual comparison is that the US isn't alone in the universe, the immigrants already exist, and they're better off in the US than not. Now if you live in a world where you believe that because you're born in the US, something which is literally a blood right, which has nothing to do with merit, affords you the unique luxury of living in the US while others do not, then sure... the first comparison is your perspective. But if you consider yourself a human being who happened to live in the US, then the latter comparison is your perspective. I mean it's obvious. Let's create an extreeeemely exaggerated comparison. Imagine a universe of twenty people, you and 9 others lived, solely, on some ocean paradise where food, health, education etc was 100% abundant, provided by sustainable robots. And you're rich, well educated, crime free etc. And then the other 10, poor people with little education, raised in a shithole environment of scarcity making him prone to crime as a tool for survival, and one of them wants to migrate to your island. Of COURSE your island will be worse off when it comes to security, education, cooperation etc, in the short term. But it still makes the world a better place to have him on the island instead of some shithole. And if carefully managed (e.g. 1 coming over every few years, resources dedicated to integrate these people, give them educational subsidies, mix them into your neighbourhoods instead of seclude them, give them representation and give them preferential treatment for jobs for the first few years), the negative effects would be minimised and temporary, and a few generations later it'd all be fine. This is an extremely exaggerated and simplified story of course (to the point it's very paternalistic, even a bit racist) but I truly feel this is pretty much what a large part of the immigration debate boils down to. I don't think anyone questions that in the short term immigration from lower socioeconomic classes has slightly negative effects, but it's not really an anti-immigration argument for me.