Abstract

This research introduces a novel convergent methodology integrating case-based observational analysis with traditional variable-based analysis. The study examines how lawful political contributions influence legislative decisions and voting behavior in the U.S. Senate, utilizing data on Political Action Committee (PAC) contributions and roll-call votes. First, correlation and regression analyses test whether PAC funding significantly associates with senators' voting patterns. Subsequently, a network analysis compares the network of PAC contributions among senators with their voting alignments based on legislative decisions. Findings indicate a positive association between PAC contributions and voting behavior: the amount of oil and gas PAC money a senator received is moderately correlated with the senator's pro-industry voting proportion (Pearson r = 0.48). At the network level, the similarity between the PAC contribution network and the voting network is slightly above random expectation but does not reach conventional statistical significance. Overall, the results suggest that PAC contributions associate with legislative voting at the individual level. The relational patterns among senators provide a complementary, albeit statistically inconclusive, perspective. This underscores the multi-layered nature of political influence in legislative processes and the value of examining contribution dynamics through senatorial interactions.