Recently, there has been much discussion about borders and immigration. However, these are secondary to the need for a spiritual border around your people, built on shared, exclusionary beliefs rooted in who you are.
As Fustel de Coulanges wrote in The Ancient City:
“The gods of the city are not, therefore, foreign gods, but domestic gods, who belong to the city, and whose worship is essential to the preservation of the city.”
For instance, to be Spartan was to worship the gods of your ancestors, binding your identity to your heritage and the divine guardianship of your city.
Sharing foreign worship makes your city vulnerable to foreign peoples who do not share your heritage, making its borders permeable to ideological conformity rather than ethnic cohesion. The latter will always suffer because of the former.
Establish a spiritual boundary by worshipping your own Gods, and the physical border will naturally follow.
