Yasmin Dawood has posted this draft on SSRN (forthcoming, Annual Review of Political Science). Here is the abstract:

This review essay considers the scholarly literature on campaign finance regulation in the United States. It charts the original debate about campaign finance regulation and its subsequent evolution in both political theory and constitutional law. It also identifies current areas of inquiry and new directions in research. In addition, it surveys some of the findings within the empirical literature in political science and economics. In terms of general trends, the scholarly treatment of campaign finance regulation has become increasingly focused on fundamental questions about democratic governance and democratic values. While the connection between campaign finance regulation and the nature of democracy has always been a subject of study, in recent years this relationship has become the predominant focus of several fields of inquiry. The topic of campaign finance regulation has generated profound debates about democratic participation, representation, free speech, political equality, liberty, and the organization and distribution of political power in government and society.