Generally the answer has been to invest in your neighbors and lift the third world out of poverty so they feel happy and secure where they are and so arent swarming your borders. That mentality seems to have lost momentum though, even here you struggle to even imagine it.
It's certainly not an inevitable situation to have pregnant women and children drowning in the rio grande tied up in american razor wire as border patrol watches on eating donuts in their air conditioned SUV's. It could've and can be prevented.