Would be very tough to implement in the US, as proposing any sort of "national ID" is pretty much a nonstarter, at least up to this point.

States could do it, and maybe agree on some protocols so that things like privacy-preserving "age verification" could be done.

Maybe the feds could push it like they did with speed limits: make federal funding contingent upon adopting e-ID. Would still get a lot of pushback.

I'm obviously not going to show my id to Zuckerberg's website or any porn sites, casinos because I don't trust those bastards. They're also not the police, so they lack the proper autoritah to request my an id.