Why have China's petrochemical and steel industries behaved so differently in seeking trade protection through antidumping measures? We argue that the patterning of antidumping actions is best explained in terms of the political economy of economic restructuring in pillar industries and its effect on industry structures. In the petrochemical industry, the shift toward greater horizontal consolidation and vertical integration reduces the collective action problems associated with antidumping petitions among upstream companies. It also weakens downstream companies lobbying in favor of the general protection of highly integrated conglomerates. In the steel industry, by contrast, national industrial policy in the absence of exogenous economic shocks fails to weaken local state interests sufficiently. Fragmented upstream and downstream channels instead persist, with strong odds against upstream suppliers waging a successful defense of material interests.