by Matthew McIntyre
Center for Competitive Politics
April 23, 2014
This study examines the effect the Supreme Court’s 2010 decision in Citizens United v. FEC has on independent spending in American politics. The authors examine the effects of Citizens United as a natural experiment on the states. Before Citizens United, about half of the states banned corporate independent expenditures and thus were “treated” by the Supreme Court’s decision, which invalidated these states’ laws. The study relies on recently released state-level data to compare spending in “treated” states to spending in the “control” states that have never banned corporate or union independent expenditures. Between 2006 and 2010, the increase in independent expenditures was more than twice as large in the treated states. Yet, the increase in spending was not the product of fewer, larger expenditures, and individuals were just as likely to make smaller expenditures after Citizens United as they were before the decision.