Why can you not just live in whatever country you want?

Answer 1

Most countries have citizenship requirements for a number of reasons. If someone lives in a particular country, this requires a certain obligation to one degree or another on the part of the society and government to care for the needs of that person. If all countries, particularly prosperous countries had an "open door policy," could you imagine the chaos that would insue? The properous countries would be overrun with people to the point of exaustion of it's resources. The quality of life in that region would become so poor that it would not be a prosperous country anymore. Other countries would lose their population to the point of possibly becoming extict, a dead nation. Another problem this would create is linguistics issues beyond comprehension. You would have people of hundreds of different languages all living in the same small area. Communication would be nearly impossible. Crime would be increased becasue without controls on who enters the country, you would be leaving the door open to whoever or whatever wants to walk in, including thieves and murderers from other countries. Although in many coutries, noteably the US, there are problems with the Immigration system, there has to be some kind of controls on immigration.