It is argued that the United States would be foolish to maintain a free-trade stance in a world in which all other countries exploit child or prisoner labor, or are protectionist

On the other hand, Ricardo's classic demonstration of the sources and effects of comparative advantage cogently demonstrates that regardless of other country policy, free trade remains the first best policy for a country to follow, since it will maximize its consumption possibilities (conditional upon other country policies). Explain. Discuss the contradiction with the argument in the preceding paragraph.

In the context of the Ricardian model, it is true that gains from trade are strictly a result of world terms of trade, which differ from domestic marginal rates of substitution. In such a world, the reason why foreign goods are cheap is of no concern to domestic consumers. However, in a world which allows for large-scale labor migration, ignoring labor conditions abroad may ultimately result in living standards for domestic workers to be dragged down.