This paper examines the role of mass media in countering special interest group influence. I use the concentration of campaign contributions from Political Action Committees to proxy special interests´ capture US Senate candidates from 1980 to 2002 and compare the reaction of voters to increases in concentration in two different types of media markets - in-state media markets and out-of-state media markets. Unlike in-state media markets, out-of-state markets focus on neighboring states´ politics and elections. Thus, if citizens punish political capture, increases in concentration of special interest contributions to a particular candidate should reduce his vote share in in-state counties relative to the out-of-state counties, where the candidate receives less coverage. I find that a one standard deviation increase in concentration of special interest contributions to incumbents reduces their vote share by about 0.5 to 1.5 percentage points in in-state counties relative to the out-of-state counties. Results are similar in specifications that rely solely on variation in concentration across time within the same county, and when the sample is limited to in-state counties that are contiguous to out-of-state counties and have similar demographic structures. A placebo test where in-state counties bordering out-of-state ones are compared to other in-state counties shows no effect, confirming the identification hypothesis that the results are not driven by geographic characteristics or distance from the media center of the state.
