As is well known, the basic economic teaching on trade policy is that free trade is by far the best option as it grants full exploitation of comparative advantages to all parties involved. Indeed, the current trade system based on multilateral agreements underpinned economic development for decades.
The overall conclusion here is that the movement of people has helped even things out across the economy. 9 / 16  BIS central bankers' speeches  The other possible explanation for the reduced dispersion in unemployment rates is that many of the economic shocks we experience nowadays are less regionally concentrated – with the mining investment boom being an obvious exception!