Net Campaign Contributions, Agricultural Interests, and Votes on Liberalizing Trade with China

We consider the potential influence of contributions from interest groups to political rivals in the voting behavior of US legislators on international trade policy issues. Our application addresses the determinants of the Permanent Normal Trade Relations with China decision, and focuses particular attention on the agriculture/agribusiness lobby. A simultaneous voting-net contributions model suggests that these contributions were very effective relative to organized labor and other corporate groups, despite their relatively small dollar value. Possible explanations arising from differences in targeting strategies are explored.