The political winds are shifting in many corners of the world, and with them, so are attitudes toward trade. The multilateral deals that came to define the global marketplace after World War II have started to sputter and stall; in their place, smaller pacts with fewer participants have begun to rise. Within this new, more compact model, the argument goes, countries are better able to home in on their core interests because there are fewer partners with which they must compromise. And though the United States may not have been the first nation to latch on to this strategy, it has certainly become the movement's poster child. ...