The general public is skeptical of our current system of campaign finance and feels that members of Congress are corrupt. Although the scholarly literature on campaign contribution influence is mixed, there is growing consensus that Political Action Committees (PACs) and interest groups do, indeed, have a powerful influence on policymaking in Congress. In this article, the author reviews this literature and discusses how influence occurs. Findings reveal that influence is only very rarely an explicit quid pro quo exchange. Instead, it is typically an ongoing, implicit, reciprocal exchange that impacts multiple stages of the legislative process and yields contributors many dividends, such as softer regulations, lower taxes, and lucrative contracts – none of which are explicitly promised (except in rare cases of full-blown bribery) but are, nonetheless, regularly granted. The social relationships between contributors and lawmakers are central to this process, as is the ability to get legislators to sway their colleagues.