Hints of queasiness from open borders advocate Nathan Smith:
A couple of years ago, I wrote a post called “The American Polity Can Endure and Flourish Under Open Borders.” I would not write that post today. The American polity might endure and flourish under open borders, but I wouldn’t claim that confidently. What changed my mind? A greater familiarity with the theoretical models that are the basis for “double world GDP” as a claim about the global economic impact of open borders, especially my own. It turns out that these estimates depend on billions of people migrating internationally under open borders. … I do not think the US polity is robust enough to absorb 1 billion immigrants (even, say, over the course of fifty years) and retain its basic political character and structure.
The large, link-dense text that follows is sure to stir up some excitement among border-stripping libertarians. As a political science fiction scenario, it has much to recommend it (including some fragmentation features that the Outer Right might find suprisingly appealing).