You can't have all good things at once. This is one of the hard lessons of life, and one that evidently needs to be learned and relearned by political liberals. Take two propositions on which they tend to agree. One is that public financing of elections is good; it removes the influence of moneyed individuals and interests. The other is that political polarization is bad; it makes it harder to reach an agreement on the expansion of the public sector.

Unfortunately for the folks who believe in these two things, it appears that you can't have both at the same time. In his invaluable and delightfully quirky Marginal Revolution blog, Tyler Cowen links to a paper by Harvard political scientist Andrew B. Hall entitled “How Public Financing of Elections Increases Candidate Polarization.” In the abstract leading off the paper, Hall writes that polarization increases “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.”

Of course, my Washington Examiner colleague Tim Carney would argue that increasing the influence of "access-oriented interest groups" is a bad thing and that “moderate legislators” are motivated less by virtuous moderation than by a desire to further crony capitalist interests from which they can make a bounteous living after they leave public office. But I'm not sure he'd approve of public financing of elections, which Hall argues reduces the influence of “access-oriented interests.” He might argue that crony capitalism supporters would just game that system as they have so many others.