The "Hayekian" argument for international currency adjustments, as made by Alex and Brad DeLong, implies that the United States needs to shift labor into its export sector, and sooner rather than later...
Brad does offer some policy recommendations, but he leaves one out. If one sees the need for a big sectoral shift at home, yuan revaluation is hardly the most direct policy instrument. China is neither our leading trade partner nor the leading foreign investor in the United States. It would have to be the case that the dollar is significantly overvalued and that market prices, not just the pegged Asian exchange rates, are all wrong. There would be a more direct solution: boost taxes on foreign investment in the United States. The demand for dollar-denominated assets would fall, the value of the U.S. dollar would fall, and the demand for U.S. exports would rise. (If we are counting only American gdp, note that this tax brings revenue to the American government, unlike yuan revaluation, which raises borrowing costs and puts a burden on Wal-Mart and on the American consumer.) Voila!
This would put both Alex and Brad in the odd position of believing that we have not enough foreign labor, but too much foreign capital.
I find it hard to accept that conclusion. And if we had the requisite betting markets, I find it hard to believe that they would (should?) reflect U.S. economic performance as improving, contingent on such a tax hike.