The subject of campaign finance is a perennially interesting and controversial one, but the interaction of money and political parties is one that has received insufficient scholarly attention in recent years. This is regrettable, as many politicians and activists have, for decades, pressed forward with a variety of political reforms to campaign finance laws in an effort to affect the behavior of political parties. Restrict the funds going to or emanating from political parties, some have reasoned, and you can reduce polarization and aid the election of more moderate officeholders. There is certainly a logic behind such claims, but they have not been held up to much empirical scrutiny.

Raymond La Raja and Brian Schaffner capably fill this lacuna with their clever book, Campaign Finance and Political Polarization. The authors make excellent work of many years of state-level data across the United States to examine the behavior of elected officials and legislatures. Specifically, they look at changes in campaign finance rules in each of the states—particularly those that directly affect parties’ ability to spend in elections—as well as state legislative polarization measures.

The main finding is that campaign finance reforms aimed at limiting partisanship have generally had the opposite effect. That is, states with more restrictions on party spending have actually seen more rapid polarization of their legislatures than those with few or no restrictions. To be sure, nearly all state legislatures have experienced some increase in polarization over the past few decades. However, “the increase in polarization was nearly three times as large in the 28 chambers that limited party contributions as it was in the 8 chambers that allowed for unlimited contributions” (p. 105).

This itself is a substantively important finding, and if the reader walks away with nothing else, that is a day well spent. But La Raja and Schaffner sift through the evidence to suggest a causal mechanism underpinning this conclusion. In particular, they examine the donation patterns of several different types of donors to campaigns. They group donors into five main categories: formal party committees, business groups, labor unions, issue activists, and individual donors.

The formal parties, the authors find, have relatively moderate donation patterns; they tend to support more centrist candidates. They do so because, as the authors note, “parties are the sole political organization whose primary goal is to win elections” (p. 2), and thus devote most of their efforts toward the most competitive districts and the relatively moderate candidates who compete for them. Other types of donors tend to be more motivated by extreme policy goals. They may end up giving to more ideologically polarized candidates to reward them for their past stances on issues and to encourage them to remain steadfast to their agenda.

This study cuts against some work, including my own, suggesting that networked parties can compensate for restrictions on formal parties by boosting spending from other areas. For example, a 2002 state constitutional amendment sharply restricted how much Colorado’s parties could spend in elections. State Democrats, at least, developed alliances with wealthy liberal activists and were able to utilize a web of 527s and other spending organizations to channel money to the races that needed it. In theory, it is the same money going to the same places. La Raja and Schaffner’s findings, however, suggest that there are ideological consequences to such a rearrangement, and that the donations would become more ideological, as would the candidates benefiting from them. (Indeed, Colorado has seen marked polarization since that time.)

The book could use somewhat greater explanation of the precise mechanism of the way in which cutting off party money produces more ideologically extreme candidates. As the authors note, most party money, where it can be spent, goes toward the more moderate candidates in competitive districts. Yet if the formal party suddenly cannot spend that money, those districts and candidates still exist. Do other partisan sources not chip in to help those candidates? It is unclear what, in the authors’ model, causes polarization in this case. Is it that the more ideological donors end up recruiting more ideologically extreme candidates for competitive districts? Is it that the moderate candidates suddenly feel greater pressure to go to the extremes to keep the extremist donors happy? There are several testable pathways here that would explain the findings the authors report, and it would be useful to examine them further.

One other aspect of campaign finance patterns that the authors note but do not reach very firm conclusions about involves difference between the parties. For example, the authors note that public opinion surveys among Republican and Democratic donors exist in which the respondents are asked to place themselves, their party, and their party’s candidates for Congress on an ideological scale. As they point out, Republican donors perceive substantial ideological differences between their party and its candidates, considering the party to be much more moderate. Few such distinctions exist in the eyes of Democratic donors. This strikes me as an important difference. However, given the timing of this aspect of the study, amidst the Tea Party insurgency, it is difficult to know just how enduring this gap is, or whether it is a long-term feature of the party system.

Similarly, if there are substantial differences between the ways that the parties finance their campaigns, it is difficult to know how or whether the authors’ recommendations, including channeling more campaign money through the formal parties, would affect the parties differently. The authors suggest that their reforms are not likely to advantage one party over the other. But the effect is not likely to be uniform across parties. Given evidence that the GOP has polarized further than the Democrats have in recent years, might such reforms have a greater effect in pulling Republican candidates back toward the center?

Despite these issues, I nonetheless strongly recommend Campaign Finance and Political Polarization. The web of campaign financing organizations only grows more complex, and the campaign financing system only grows less transparent, with each passing election cycle and in response to each new court decision. Reformers continue to advocate for driving money out of politics and for ending party polarization, but as these authors make clear, pursuing one goal often undermines the other. La Raja and Schaffner’s perspective is a vitally important one for the ongoing public debate on campaign finance and other political reforms. We should be loath to undertake these kinds of reform without such a thorough examination of their potential for futility or even perverse outcomes. While the book’s analysis is sophisticated, the authors explain it well and keep it accessible for undergraduates. It is also well geared toward political activists and reformers, who could learn a great deal from it.