In many preferential trade agreements (PTAs), countries exchange not only reductions in trade barriers but also cooperation in non-trade issues such as labour and environmental standards, intellectual property, etc. We provide a model of PTAs motivated by cooperation in non-trade issues and analyse its implications for global free trade and welfare. We find that such PTAs increase the cost of multilateral tariff reductions and thus cause a stumbling block to global free trade. This occurs because multilateral tariff reductions decrease the threat that can be used in PTAs and thus the surplus that can be extracted from them. By explicitly modelling the interaction between preferential and multilateral negotiations, we derive a testable prediction and provide novel econometric evidence that supports the model's key prediction. The welfare analysis shows that the current World Trade Organization rules allowing this type of PTAs may be optimal for economically large countries, thus the model can predict the rules we observe. We also analyse alternative rules that constitute a Pareto improvement.

Most countries are members of preferential trade agreements (PTAs). The effect of these agreements has attracted much interest and raised the question of whether PTAs promote or slow multilateral trade liberalization, i.e., whether they are a “building block” or “stumbling block” to multilateral liberalization. Despite this long-standing concern with PTAs and the lack of theoretical consensus, there is no systematic evidence on whether they are actually a stumbling block to multilateral liberalization. We use detailed data on U.S. multilateral tariffs to provide the first systematic evidence that the direct effect of PTAs was to generate a stumbling block to its MTL. We also provide evidence of reciprocity in multilateral tariff reductions.

We find that prior to World Trade Organization membership, countries set import tariffs 9 percentage points higher on inelastically supplied imports relative to those supplied elastically. The magnitude of this effect is similar to the size of average tariffs in these countries, and market power explains more of the tariff variation than a commonly used political economy variable. Moreover, US trade restrictions not covered by the WTO are significantly higher on goods where the United States has more market power. We find strong evidence that these importers have market power and use it in setting noncooperative trade policy.

We examine the impact of policy uncertainty on trade, prices, and real income through firm entry investments in general equilibrium. We estimate and quantify the impact of trade policy on China's export boom to the United States following its 2001 WTO accession. We find the accession reduced the US threat of a trade war, which can account for over one-third of that export growth in the period 2000– 2005. Reduced policy uncertainty lowered US prices and increased its consumers' income by the equivalent of a 13-percentage-point permanent tariff decrease. These findings provide evidence of large effects of policy uncertainty on economic activity and the importance of agreements for reducing it.