Trade vote determinants: Partisan effects of political action committee contribution percentages

Free trade agreements are less likely than other major congressional roll call votes to be decided by party affiliation, and are therefore regarded as opportunities to test the impact of interest group influence in the observable form of campaign donations. In this project, the vote to normalize trade relations with China is analyzed by variables including the percentage of total campaign donations from either labor or business. The data indicate that higher percentages of labor contributions, or relative interest group support, raised the probability that a member would vote against the trade bill, and the effect appeared more pronounced among Republicans than Democrats.