What problem do trade agreements attempt to solve? An answer to this question is necessary to understand trade agreements. For years there has been a consensus among economists that the fundamental role of a trade agreement is to prevent the prisoner's dilemma that results from nations using trade policy to manipulate their terms of trade to their own advantage. favor. But this consensus has been challenged by the possibility that other reasons for trade protection may emerge in the presence of imperfect competition. A government can also use trade policy to attract profits, employment, and businesses within its borders. This variety of motivations then raises the question of whether there is a purpose for trade agreements distinct from that found in the perfectly competitive benchmark. My proposed thesis restores the previous consensus behind the terms of trade rationale for trade agreements. I consider trade agreements in a fairly general context that imposes limited assumptions about consumer preferences, government preferences, and market structure. Despite the various motivations behind trade policy, I believe that trade agreements are always efficient if they force governments to act or if they do not enhance the rents resulting from improvements in the terms of trade. Having established this result, I can proceed to provide a more robust interpretation and assessment of the WTO principles. Considering the fairly general preferences of consumers and governments, my theory of trade agreements reports a desirable feature of the perfect competition literature that has yet to enter the market. imperfectly competitive literature. The seminal paper on perfect competition, Bagwell and Staiger (1999), allowed not only the case in which governments maximize income, but also the case in which governments s...... series of papers by Bagwell and Staiger (2001a, 2001b), where the WTO's focus on market access actually leads to efficiency, and counterfactual governments would never want restrictions on specific national policies to prevent a race to the bottom in national production standards I intend to establish the conditions under which governments do and do not want restrictions on specific national policies. My article “Domestic Policies in Trade Agreements When Firms Matter” details a specific case where governments want such restrictions and WTO rules do not lead to efficiency. But like Ossa (2009), this result is based on exogenous restrictions on governments' use of export policies. I intend to investigate whether this result extends to the more relevant context in which export policy restrictions are endogenous.