Thus, changing preferences among political leaders and societal groups,
institutional changes (especially democratization), and the increased influence of international institutions that supported trade liberalization may best explain the global rush to free trade witnessed since 1980. Research on this puzzle is certainly not complete, however. None of our existing theories by itself seems to do very well in explaining this movement, the most important change in trade policy globally since the end of World War II, and none appears to have predicted it. A better understanding of how political leaders form their trade preferences and how these preferences are connected to societal ones is essen- tial. Moreover, theories about the relationship between democracy and trade are in their infancy. Knowledge of the conditions under which international insti- tutions are able to exert greater (or less) influence over countries is necessary.
Finally, we need to know whether the rush to free trade will be sustained or
reversed. Will trade barriers remain as low as they are and keep declining, or will protectionism return? Again, I suspect that the factors that are responsible for the initial change may have some bearing on this. If leaders’ or social
groups’ preferences for free trade are maintained or grow, then we might ex- pect liberalization to remain in place. Factors, such as economic crises, that cause actors to question these preferences will limit their sustainability. We might also expect that the return of authoritarian governments would be asso- ciated with the return to protection, but democracy itself is not a sufficient condition for liberalization. Finally, the role of international institutions seems to be heightened by the severity of domestic economic crises. This suggests that, as good times return, political leaders who do not favor free trade may re- ject the policies forced on them by their lenders and turn protectionist. These and other factors will be important for understanding the sustainability of trade liberalization. Our existing theories are perhaps even less helpful in explaining sustainability than they are in explaining why countries liberalized in the first place.
ACKNOWLEDGMENTS
I wish to thank David Baldwin, Jeffry Frieden, Stephan Haggard, Robert Jer- vis, and Dani Rodrik for their very helpful comments on an earlier draft of this paper.