It always surprises me that people talk about "immigration" as if it's a binary field, either on or off. To me, it's all about degree. There's an ideal level

It always surprises me that people talk about "immigration" as if it's a binary field, either on or off. To me, it's all about degree. There's an ideal level of immigration - go too high over it, and it leads to overcrowding, social upheaval, displacement. Go too low, and a society stagnates. It's not just about numbers, of course, it's also about the type of immigrant. While it may be politically incorrect to say so, migrant farm workers who send most of their earnings home may very well result in a net loss, whereas highly educated workers result in a net gain. The issue is so intense in the US that I think it's productive to ask how you'd design an immigration system for a smaller country with lower population density. Right now, New Zealand has a population of about 4 mil and a land mass only a bit smaller than California. Would New Zealanders be better off if fifty million immigrants came into the country over the next 20 years? If not, how many immigrants would you consider to be ideal? It's not all about GDP - it's a beautiful country, essentially a giant national park, and that would be lost if they allowed mass immigration.