[smallnamespace]

We're talking about in the context of economic relations, which are entirely human-created constructs. Under that definition, everything is artificial.

Fact of the matter is that every nation in the world has labor and passport controls. It would be exceptional and unusual for the US to abandon them unilaterally.

[Hondor]

They could open the border with Mexico, just as the UK opened the "border" with Poland. If that happened, it would be undeniably a freeing of the labor market. That means the participants are individually deciding where to go, rather than other people who aren't directly involved in their trading. It might be unlikely but just because a situation is the status quo, doesn't make it natural or free.

The Soviet Union lasted a long time without a free market. Yet nobody would say allowing sellers to choose their own prices is artificial because they've been dictated by the government for decades and that's the normal and natural state of things.