It looks to me like nationalism with free trade means that all countries in the world would pay their workers a fair and living wage so that nobody would need to (or feel the need to) leave their country of origin and go to another country to live because they don't feel they can have a good standard of living in their own country. Personally, I think it would be excellent if this were the reality, and I think most of the people who are currently having to leave their own countries for economic reasons would agree with this.