One of the things that distinguishes American nationalism from most othe modern forms is the pseudo-religious nature of it all. The US Constitution is treated like a holy text, and unchanging and unchangeable font of wisdom that must be read carefully to discern and interpret the message of the prophets (aka ‘the founders’). Similarly national symbols obtain a kind of quasi religious status which is why some want to outlaw burning the flag. This is all well known and has been often described, often given the name the American Civil Religion.
Within this context immigration is a process of religious conversion and anyone who’s spent time listening to both immigration stories and stories of religious conversion (including anyone who’s spent a significant amount of time in the Bible Belt) can’t help but notice the parallels:
*The immigrant is unhappy or frustrated or maybe even in danger in their homeland.
*Through great effort they emigrate and come to the US.
*Despite difficulties and obstacles they become enthusiastic Americans and achieve a state of grace that would have been impossible in their homeland “Only in America!” and they want to raise their children to be happy and fulfilled Americans too.
Of course the real world is not so tidy and immigration is also full of stories of failure and loneliness but those are stories of backsliding and reversion to an unsaved lack of grace. The cousin who couldn’t make it America and returned home can still be prayed for and maybe pitied, but it’s not a story to publicize or emulate.
This is one reason that many people are hesitant to secure the border – it’s like locking the church when the spiritually lost are looking for salvation. Divine grace is limitless and the more a person has internalized the American Civil Religion the less likely they are to want to cut off the road to salvation to others.
The other reason is that progressives (who have internalized the religion as much as anyone else) are liable to be unhappy with the state of the country (as having lost its moral way or suffering from original sin at its base) and see immigrants, especially undocumented ones as a kind of redeeming force.
There’s more to say about this and I might, but a lot of otherwise irrational and downright dysfunctional public posturing about immigration makes perfect sense if you see it as a story of the saved going out of their way to help potential converts become true believers.