The popularity of televised political advertising has continued expanding over recent years, and now frequently attracts candidates for lower-level offices such as the House of Representatives, and even State Senate or Representative. Among its effects, this is leading to targeted voters being increasingly inundated with political solicitations in the weeks before an election. Political science has been creative, but limited, in overcoming many of the challenges presented in the field of media effects as it has endeavored to understand the basic effects generated by political media campaigns. One dearth of knowledge is a proper understanding of how varying levels of surrounding political volume might impact voter behavior and candidate evaluations. To that end, this research aims to uncover evidence of wider media market effects on the persuasive power of campaign ads. By merging voter opinion surveys with observed campaign media activity leading up to the 2014 midterms, and fielding a first-of-its-kind laboratory experiment which manipulates the amount of political information viewed, I find evidence that increasing volume and diversity of the surrounding political information in a media market significantly reduces the persuasive power of political ads. As campaigns spend more money on television advertising, these results suggest the need for a serious shift in how campaigns target and speak to voters in crowded market environments, expanding their view of relevant competition from the activity of their electoral opponent to all political actors in the greater media market. Moreover, these results suggest that some congressional candidates may need to “own” large majorities of their media market’s total political advertising to have any hope of counteracting these overexposure effects. This research also has major implications for how academics study campaign media effects, suggesting that results from isolated examinations of individual candidates or contests may be distorting our predictions of expected persuasive lift on broadcast television.