A Test of the Structure of PAC Contracts: An Analysis of House Gun Control Votes in the 1980s

Abstract

Enactment of the bill was a major victory for the National Rifle Association, which had worked for years to win relaxation of the landmark Gun Control Act of 1968. Congressional Quarterly Almanac (1986, p. 82) I. Introduction Every election the same political action committees (PACs) contribute millions of dollars to candidates for office. Well-informed participants in the political process surely must get value for their money. Yet empirical research fails to provide systematic evidence that campaign contributions influence congressional roll call votes.1 A mischaracterization of the exchange between PACs and politicians may produce these contradictory results. Empirical studies of roll call voting typically use PAC contributions from only one election cycle. Earlier studies generally assume prepayment in the prior Congress, while more contemporary studies assume a spot exchange. Recent empirical work, however, suggests another possibility: Interest groups may buy current influence with money spent over multiple election cycles. Stratmann (1995) shows that contributions from both the current and the previous election cycles influence floor votes on agricultural price supports. Snyder (1990, 1992) presents evidence that interest groups make long-term investments in politicians. Previous studies, by arbitrarily imposing a payment structure, may have produced erroneous estimates of the influence of PAC money on legislative votes. We examine roll call votes on gun control in the U.S. House of Representatives during the 1980s to determine whether PACs make spot market purchases, prepay for votes in the prior election cycle, or make long-term investments. We investigate whether PAC contributions have a durable, long-term investment effect, as Snyder (1992) suggests. We consider two types of evidence concerning the campaign contribution contract. First, we examine the pattern of expenditures by the two dominant interest groups concerned with gun control: the National Rifle Association (NRA) and Hand Gun Control (HGC). Their expenditures provide strong evidence against the spot market exchange hypothesis: Both groups made significant expenditures in sessions of Congress in which no floor vote occurred. Nor were these expenditures purchasing services such as committee work in a spot market exchange. Further, 1986 NRA expenditures are significantly higher for first-term representatives, which is consistent with long-term investments but contradicts a spot exchange (since freshmen have the least influence to sell). Second, we include expenditures from both the current and the five previous election cycles as separate independent variables in a model of roll call voting. To date, no empirical paper tests whether PAC money from more than two cycles influences roll call voting, and only Stratmann (1995) and Grenzke (1989) use a model that specifies money from more than one cycle in an equation explaining roll call votes. Our probit estimates indicate that NRA expenditures in the three most recent election cycles and HGC expenditures in the two most recent cycles buy votes. The independent effect of expenditures from different cycles suggests that contributions are neither an unqualified one-session prepayment nor a spot exchange. The influence of NRA expenditures two sessions prior to the roll call votes is evidence of a long-term investment. The literature on the determinants of roll call voting assumes that PAC contributions alter representatives' votes. Interest groups might instead simply provide campaign assistance to their supporters to affect the composition of Congress (Stratmann 1991; Bronars and Lott 1997). If a difficult to quantify variable (and thus omitted from regressions) signals a representative's true position and interest groups make campaign contributions on the basis of this variable, PAC contributions might appear to influence votes. The pattern of contributions and votes on gun control, however, indicates attempts by the NRA and HGC to influence votes, not merely the composition of Congress. …