As readers of this blog know, I am very much in favor of open borders (that is, the free movement of peaceful peoples across international borders). I promote this policy on moral ground and on principle. However, I wonder if there isn’t a reason to promote open borders for the sakee of advancing liberty in other means, namely free trade (which can be described as the free movement of peaceful capital across international borders). (Warning, a bit wonky)
How would this work? Like this:
So, if workers are prevented from emigrating from their current lands, they will have to work in their homelands. However, since they are less productive in their homelands (or remain unemployed), their wages would, naturally, be lower in comparison to a more productive workforce (like the US); remember that wages are determined by marginal productivity. After all, that would be the economic reason for emigrating: better (ie more productive) opportunities elsewhere.
Assuming that the home country trades on the world market, its workers could have a wage-advantage that could lure some production from higher wealth countries to the lower wealth countries (similar to how the US has relocated some factories to China). The higher wealth nations could lash out with tariffs or taxes on the newly imported goods because of “unfair labor practices” (paging Mr Trump or Mr Sanders). These resulting tariffs would, necessarily, result in less-free trade and could even result in a trade war. Furthermore, both countries would be deprived of the productive benefits the increased division of labor would have created, leaving both nations less wealthy than they would have been otherwise.
So, at last hypothetically, open borders could help promote the idea of free trade naturally (and, by contrast, closed borders would lead to less free trade).
PS: Please forgive any and all spelling mistakes. I am writing this post from my Samsung Tab and, for some reason, it doesn’t have spellcheck.