Either allow labor to always move as freely (or a un-freely) as capital & profit, or move back towards less international trade, certainly between countries with highly disparate income levels and legal systems.
When you use the word "labor" do you mean literally it has to be people who work or do you think any human should be able to move about freely?
I ask because international trade, capital, etc. don't move around without rules & regulations. For instance, I can't just move all my wealth between countries without scrutiny, fees, taxes, etc.
This is the "RETVRN" that I would love to see. Make the USA pre-1882 again (year of the first immigration-related law in the US: the Chinese exclusion act).
Let people live where they want, everywhere in the world. Good places will draw population and prosper, and bad places will stagnate until they change.