In a new paper for the Mercatus Center, Adriana Cordis and Jeff Milyo use a number of statistical tests to measure the effect of campaign finance reforms on public corruption:
[W]e find no strong or consistent evidence that state campaign finance reform reduces public corruption. This finding is true regardless of whether the reform in question is a limit on corporate or individual contributions or some form of public financing. […]
These non-results are substantively important because the courts effectively have placed the burden of proof on the government to show that campaign finance regulations reduce corruption.
Our findings are consistent with other research that demonstrates an absence of any treatment effect of state campaign finance regulations on public trust and confidence in state government […] . While these results may not surprise scholars of American politics, they are at odds with the popular wisdom that many politicians, reform advocates, and media pundits espouse. Further, the apparent impotence of campaign finance regulations in ameliorating the “actuality or appearance of corruption” has dramatic implications for the longstanding legal rationale for all existing campaign finance regulations. Heretofore, many judges and legislators have considered it self-evident that restrictive campaign finance regulations are a prophylactic for public corruption. We find that this presumption is baseless. [Internal citations omitted.] [“Do State Campaign Finance Reforms Reduce Public Corruption?” by Adriana Cordis and Jeff Milyo, April 2013]