5. In the 1980s, migration was explained with the urban bias theory which was promoted by Michael Litpon who wrote: "...the most important class conflict in the poor countries of the world today is not between labor and capital. Nor is it between foreign and national interests. It is between rural classes and urban classes. The rural sector contains most of the poverty and most of the low-cost sources of potential advance; but the urban sector contains most of the opportunities, organization and power. So the urban classes have been able to win most of the rounds of the struggle with the countryside..."