Langbein, L.I. Public Choice (1993) 77: 551. doi:10.1007/BF01047860
Previous research has shown that PAC contributions from the National Rifle Association as well as letters and lobbying by Handgun Control, Inc. significantly affected Congressional voting on the Firearms Owners Protection Act of 1986, holding constant ideology, party, constituency characteristics, and a proxy for prior position on the issue. Using data from that study, this paper shows that contributions have a somewhat different effect than lobbying. Contributions from NRA were primarily targeted at NRA supporters and had the net effect of making the progunners even more so. Contributions from Handgun Control, while they did not significantly reinforce the proclivities of the gun controllers, were directed only at that group. At least in this case, money appears to exacerbate conflict. By contrast, the police lobby directed its attention at both gun controllers and pro-gunners; the lobby effectively induced pro-gunners to moderate their position.
These findings are consistent with the hypothesis that PACs associated with membership groups, which seek to retain members whose primary reason for joining is self-expression, are likely to allocate monies in such a way as to exacerbate policy conflict and to allocate lobbying activities so as to induce moderation. Nonetheless, because the gun issue is unidimensional, the finding that money fosters conflict implies only that Congress will be noisy, but not in disequilibrium.