^ Edward Feser wrote an article that sums on Aquina's views on globalism and the fallout that results from it (open border immigration) that I found insightful
In Book Two, Chapter 3 of his little work De Regno (or On Kingship ), Thomas Aquinas addresses matters of trade and its effect on the mate...
The principle here is that becoming part of a nation is, again, not merely a matter of entering into the population of some geographical territory. It also involves making one’s own the common history, laws, mores, and culture of that nation – joining the extended family, as it were. Until that happens with an incoming population, it cannot, in Aquinas’s view, be sure to have the nation’s “common good firmly at heart.”
What these passages from Aquinas imply is that too free a flow of populations across borders tends to dilute allegiance to the shared norms and culture of a nation, and thus threatens national unity. For, on the side of citizens, out of deference to foreigners they will become less attached to those norms and that culture, and thus less attached to their own nation; and on the side of foreigners, they will feel less incentive to adopt or respect the norms and culture themselves, and thus less likely to assimilate to the extended family.