> have their visa applications denied on public charge grounds

Oh, I wasn't familiar with the 'public charge' requirement of the US immigration system. That's excellent in principle, and wonderful if enforced adequately.

> Not sure how that works with Medicaid—it sounds like [1] some states have chosen to implement that in ways immigrants can access if they come in on green cards and spend their working lives in the US, paying in to the system—but that seems to me more like a local policy choice than a primary feature of the immigration system.

Yes, agree that's not a feature of the immigration itself but a local policy choice. Some states are very lax with Medicaid qualification rules eg, California recently expanding coverage to illegal immigrants with loosened criteria that legal immigrants won't qualify. I recall changes were made in response to federal tightening of rules. It's still a bad policy, but a local one.

> For that matter, in your formulation, should the working-age immigrants themselves, who permanently resettle and work their whole life in the US, be denied access to old-age benefits when the time comes?

No, one principle is they have paid into the system for a long period of time then they should of course be able to access benefits.

The other principle is by that time they are ready to retire they will certainly permanent residents but hopefully citizens, so not seen differently than other citizens.