LE could do more today true, but if there were no borders at all how would they not be overwhelmed? They don't even have the law successfully enforced at the mo

LE could do more today true, but if there were no borders at all how would they not be overwhelmed? They don't even have the law successfully enforced at the moment, let alone in a world where nothing stops people moving at all. And what stops illegals just being self employed? Why (do you think) "gang members and dealers" are coming to America? Ah sorry. I interpreted "they" as "all people crossing a border". My point is raids on employers only catch cases where people are working for legitimate employers. If that's all you rely on, you can't try to filter out people who have alternative illegal income streams before they enter the country and become much harder to find and deal with. I would be interested in a system whereby an internal border is so effective no external border is needed. But it's not clear to me it'd actually be better: there'd have to be constant checking of identity documents all the time, hugely ramped up law enforcement, and without a border it's unclear deportation would mean anything at all. People could just turn around and come right back in. It'd be sort of like trying to solve theft by just spending lots of money on police but not having door locks anywhere. There's a fundamental mismatch of costs.