It seems like everyone can agree that we need immigration reform. We need to control our borders somehow. But what are borders for?
When civilizations were small pockets of people separated by vast wilderness or bodies of water, borders were not necessary. After these pockets grew large enough to bump into each other, borders naturally developed.
Borders indicate which population group has claim to a given piece of land. That claim allows them to farm the land, mine the land, use its water, and live there. When two or more peoples claim the same piece of land, the dispute often is settled by war. The stronger group typically wins.
Borders, then, separate neighboring peoples. Borders identify by location "us" and "them." Many times the different people groups look different, and can be identified by personal appearance as well as location.
Borders serve as a way of sorting out the world's population, a kind of filing system to know who belongs with whom.
Historically many borders have been marked by barriers. Hadrian's Wall and the Great Wall of China were both built to keep out troublemakers who were "them."
In modern times we think of the Berlin Wall, which was designed to keep people in, not out.
The people in power, the ones with authority, and guns, bricks and masons get to decide where the walls go and whether the walls keep people in or out. Either way, the walls are used for restricting the movement of some people. Certain people are prevented from going where the people in power don't want them to go.
It's easy to get all self-righteous and say that all these walls should be dismantled. But I live in a house with walls. The walls help keep me warm and cool at appropriate times. But the walls also keep the wrong people away from my stuff and my family. These walls are a kind of border for me.
I bet you live in a house with walls, too.