Every nation has the right to distinguish, by country of origin, who can migrate to it and apply appropriate immigration policies, according to the great medieval scholar and saint Thomas Aquinas.
In a surprisingly contemporary passage of his Summa Theologica, Aquinas noted that the Jewish people of Old Testament times did not admit visitors from all nations equally, since those peoples closer to them were more quickly integrated into the population than those who were not as close.
Some antagonistic peoples were not admitted at all into Israel due to their hostility toward the Jewish people.
The Law “prescribed in respect of certain nations that had close relations with the Jews,” the scholar noted, such as the Egyptians and the Idumeans, “that they should be admitted to the fellowship of the people after the third generation.”
Citizens of other nations “with whom their relations had been hostile,” such as the Ammonites and Moabites, “were never to be admitted to citizenship.”
“The Amalekites, who were yet more hostile to them, and had no fellowship of kindred with them, were to be held as foes in perpetuity,” Aquinas observed.