The Monkey Cage has an interesting discussion about whether boosting turnout would reduce levels of polarization and partisanship among our elected officials. While none of my work directly addresses the question of the effect of general election turnout on polarization, several of its strands would place me clearly in John Side’s camp of skeptics.

• Chapter 4 of Polarized America analyzes trends in turnout among different income groups during the period of expanding polarization (1972-2004). There were several important take aways. The first is that our evidence is consistent with earlier findings of McDonald and Popkin that there is no trend in turnout among the voting eligible population (VEP) (roughly citizens over 18 who are not disqualified due to felony convictions). The downward trend in participation by the voting age population (VAP) (all residents over 18) is caused by increased numbers of non-citizen residents and (to a lesser extent) disenfranchised felons. Moreover we find that the relative incomes of voters and non-voters are roughly constant over the time period. So it would seem that trends in turnout could hardly explain the increase in polarization. Indeed, reversing the trends in VEP would mean reversing disenfranchisement laws and allowing non-citizens to vote. It would be reasonable to expect that those reforms would shift the spectrum to the left but not de-polarize it.

• My other relevant work concerns the effects of participation in primary elections. In this rejoinder to Richard Pildes, I report some estimates of the effect of primary election turnout on the extremity of a House member’s NOMINATE score. A key problem for such analysis is that turnout may itself be influenced by a candidate’s position. So I use the coincidence of competitive presidential, gubernatorial, and Senate primaries as exogenous variation in turnout. The resulting IV estimates show no relationship between turnout and the winner’s NOMINATE score. I concede, however, that the effect of the instruments (the competitive primaries for higher office) is small. The second piece of evidence is reported in my working paper with Eric McGhee, Seth Masket, Boris Shor, and Steve Rogers. Here we find little evidence that the institution form of primary election effects polarization of state legislators. This undercuts the common argument that open primaries reduce polarization by boosting participation.

But perhaps the most relevant piece of information about Bill Galston’s original contention that mandatory voting would reduce polarization is a new paper by Anthony Fowler at Harvard. In a careful study, he looks at the effects of the adoption of compulsory voting in Australia. He estimates that the causal effect of compulsory voting was a significant boost the left-wing Labour Party. So the effect of compulsory voting appears to have shifted Australian politics to the left rather than shore up the center.