The Purpose of Government

It seems to me that the purpose of government is to establish and maintain an environment where conditions can improve.

This would surely include protecting the borders of the area governed. But would it include expanding those borders? Perhaps there are some conditions in which it would.

What about general protection of citizenry? From what or whom? From each other and people outside. But not from themselves, I’d say. That is, it is someone’s right to cause harm to himself if doing so does not cause harm to another person or another person’s property.