Yet another shibboleth of campaign finance reform appears to be in weak shape, here is a new paper (pdf):
I show that the public funding of elections produces a large decrease in the financial and electoral advantage of incumbents. Despite these effects on electoral competition, I demonstrate that public funding produces more polarization and candidate divergence|not less. Finally, I establish that this effect is at least in part due to the fact that public funding disproportionately affects the contribution behavior of access-oriented interest groups, groups who, I show, systematically support moderate incumbents. Access-oriented interest groups therefore help generate the incumbency advantage and mitigate polarization by supporting moderate legislators.
That is from Andrew B. Hall at the Department of Government at Harvard.