These claims, however, are more wishful thinking than actual truths. Consider the first idea, that a strengthened Chinese currency would increase the growth rate of American exports to China. From 2005 to 2008, the renminbi appreciated nearly 20 percent against the dollar. Yet, American exports to China over those three years grew at a slightly slower pace than in the previous three-year period when the renminbi did not appreciate at all (71 percent versus 89 percent).

This is because many of America’s top exports to China are for capital-intensive goods like aerospace and power-generation equipment. Price is but one of several factors for these purchases, along with technology, quality and service. In addition, American companies in those industries are usually competing against European and Japanese firms rather than Chinese manufacturers. Ultimately, the dollar-euro and dollar-yen exchange rates may play more important roles in Chinese demand for American goods than the renminbi rate.

Second, I recently did an analysis of the top American exports to our 20 leading foreign markets, and found little evidence that an undervalued Chinese currency hurts American exports to third countries. This is mostly because there is little head-to-head competition between America and China. In less than 15 percent of top export products  for example, network routers and solar panels  are American and Chinese corporations competing directly against one another. By and large, we are going after entirely different product markets; we market things like airplanes and pharmaceuticals while China sells electronics and textiles.

Finally, it is unlikely that a stronger renminbi would bring many jobs back home. Instead, companies would most likely shift labor-intensive production to Vietnam, Indonesia and other low-wage countries. And in any case many high-skilled jobs will continue to flow overseas, as long as cheaper talent can be found in India and elsewhere. Only in a few industries, like biomedical devices, would a stronger Chinese currency combined with quality issues tempt American companies to keep more manufacturing at home.