We analyze the interaction between a domestic firm and an international trade agency in charge of administering an antidumping procedure by means of a model in which dumping is viewed as an “aggressive” behavior of foreign firms against domestic firms of a relatively low-efficiency type. An informed and benevolent agency grants protection exclusively to this type of domestic firms. We introduce asymmetric information about the domestic firm's efficiency and let the agency's decision be influenced by the firm's choices of output and lobbying contribution. We characterize (pure-strategy) equilibria the properties of which shed some light on the way politics and economics interplay in antidumping, and perform a comparative statics analysis that highlights some of the benefits of reforming antidumping laws.