I. Introduction By the early 1980s, Canada-United States international trade was the largest bilateral trade flow in the world. In order to reduce its vulnerability to unilateral action from the United States through its foreign trade policy, the Government of Canada requested a comprehensive free trade agreement with the United States (as set out by the MacDonald Royal Commission) in 1985. This request was made despite the fact that in 1985, 85 percent of all Canadian exports to the United States crossed the border duty free, with the remaining average tariff rate being 4 percent--these zero and low tariff rates were in large part due to the Canada-United States Automotive Products Agreement of 1965 and Canada's dedication to the successive rounds of the GATT negotiations (Coffey et al. 1999). In anticipation of the effects of a free trade agreement between Canada and the United States, economists began assessing the potential impact of this substantial policy change in the mid-1980s using computer simulations. These simulations, built on the seminal work of Harris (1984), use a simplified model of the economy, impose a policy change (shock) on the economy, and calculate the change in the economy as a result of that policy change. This is done by gathering actual data on inter-industry transactions, factor payments (wages, interest, etc.), final demands for goods (consumption, investment, government expenditures, etc.), and making some simplifying assumptions regarding economic behavior. Further, assuming that the observed (real) data is in (short-run) equilibrium, the relevant policy parameters (tariff rates, etc.) are altered, a new equilibrium is calculated, and the change between the two equilibria is measured (Kehoe and Kehoe 1995). These models of the economy are usually referred to as applied general equilibrium models. They are popular because they can assess the impact of reallocating resources between industries, and determine the winners and losers differentiated by industry, region, or both, that result from the policy change. Unfortunately, these models of the economy are highly simplified versions of the actual economy with many simplifications such as a limited number of aggregated industries (typically 15-35) and the policy change is instantaneous. In the case of free trade agreements, all tariff rates and non-tariff barriers are removed at the implementation of the policy change. Therefore, any results should be taken with a grain of salt, interpreted and evaluated with caution. Nevertheless, they do provide a view into the future worth noting. Though the different studies using applied general equilibrium analysis all differ along the number of industries in the economy, how many countries are modeled, and market structure, the results are all qualitatively similar. The effect of the CUSFTA is positive for Canada, with the increases in real GDP ranging from 1.6 percent (Jenness 1987) and 4.5 percent (Cox 1994) to 11 percent (Roland-Holst et al. 1994)--these gains all take 8-10 years to materialize and are in addition to any growth in the economy independent from the CUSFTA. NAFTA, from a Canadian perspective, is quite different. The general result is that Canada has zero, or essentially zero, gains from the NAFTA over and above the gains from the CUSFTA (Kehoe and Kehoe 1995). Using the CUSFTA results as a benchmark, Cox and Harris (1992) and Cox (1994; 1995) find that Canada has small (though positive) gains from the NAFTA, particularly with respect to changes in the trading relationship with the United States. Relatively speaking, Canada-Mexico international trade increases significantly, 57 percent, but due to the small base level of trade, this increase has little effect on the Canadian economy. Brown et al. (1992) reports a significant positive effect of the NAFTA for Canada, but the magnitude, though larger than the Cox and Harris (1992) and Cox (1994; 1995) results, is low. …