While political parties remain the organizations that most commonly knit together legislators in modern parliamentary bodies, they hold no such thing as a monopolistic grip on the allegiances and activities of their members. Scholars in legislative studies have long recognized that committees can, under certain conditions, demonstrate their independence from the floor and from party leaders. In other cases, subnational state and regional delegations can attract the effort and identity of legislators. Yet political scientists are ever more turning their gaze to other organizations that connect lawmakers, whether as factions (like “Blue Dog Democrats”) or caucuses, or as issue-specific networks that connect legislators for informational purposes. These within-chamber organizations compose the subject of the first comprehensive comparative treatment of “legislative member organizations” and the networks composing them.

In Bridging the Information Gap, Nils Ringe, Jennifer Nicole Victor, and Christopher J. Carman argue that legislative member organizations function in part to solve a collective action problem regarding the supply of policy-relevant information. The book takes its place in a small but growing literature on comparative legislative behavior and lawmaking, with a focus on interlegislator networks as its central contribution. Both its successes and its limitations point to the transformations that need to occur in political network science in the coming years.

The authors differentiate legislative member organizations (LMOs) from political parties by using ideas from transaction-cost political science as well as network analysis. LMOs are less formal than parties and offer few binding constraints upon their members. They are, rather, voluntary organizations that exploit “weak ties” among their members to bridge diverse and otherwise little-connected members. Unlike parties, LMOs control neither ballot access nor committee assignments. They lack both the differentiated hierarchies and whip-capable systems that parties can use to discipline votes. Just as crucially, they do not control the strings of campaign finance. Instead, they serve as the organizational housing for interlegislator social networks. In so doing, they “allow legislators to build relationships with each other,” such that “the social networks composed of these relationships provide for an efficient exchange of high-quality information inside the chamber” (p. 18). Yet the apparent weakness of LMOs conceals an asset, namely, that in both Europe and the United States, they appear to be intimately involved in the process of getting legislative work done.

This book thus joins a small but rapidly growing literature on intrachamber and intraparty organizations. Most of the literature concerns caucus organizations in the U.S. Congress, led by the writings of Susan Webb Hammond and, later, Scott Ainsworth and Frances Akins. Most recently, and in the setting of the Congress, Kristina Miler has connected caucus membership to reelection incentives and to “constituency motivations” (“The Constituency Motivations of Caucus Membership,” American Politics Research 39 [2011]: 885–920), and Ruth Bloch Rubin offers a fascinating reinterpretation of the Cannon Revolt in her examination of intra—Republican Party organization during the Progressive era (“Organizing for Insurgency: Intraparty Organization and the House Insurgency, 1908–1910,” Studies in American Political Development 27 [no. 2, 2013]: 86–110). Like the work of Hammond, Ainsworth and Akins, and others, Bridging the Information Gap identifies the informational value served by LMOs. Unlike most of the previous literature (with perhaps the recent exception of Rubin), Ringe, Victor, and Carman examine networks that become factions of a sort, and explain how and why they organize. The effect of LMOs on legislative outcomes is not direct in the sense of shifting votes or directly establishing the agenda, the authors claim. The true value of LMOs is to be found in placing particular issues and ideas on the legislative agenda and keeping them there (pp. 185–98).

The authors embed their theoretical framework, their hypotheses, and their empirical analysis in network science, and the effort pays off. It is precisely the weak-tie nature of LMOs, precisely the fact that interlegislator links through LMOs are “ties that do not bind,” that accounts for high-quality information sharing (p. 136). Only when lawmakers come into LMOs from across parties, across regions, and across ascriptive groups can unique information sharing occur that is not already supplied by the rusted pipes of existing institutions and allegiances (pp. 125–41). If cosponsorship of bills is any guide, LMOs and their network characteristics account for patterns of legislator cooperation for which attribute variables such as party, geography, and individual characteristics, and mere caucus membership explain little of the variance (p. 198). This dimension of interlegislator networks is compelling and advances far beyond the cosponsorship-centered literature on legislative networks.

If this literature is to move forward, however, scholars like these authors and their successors will need to get more historical in their approach to networks. The networks examined here are almost entirely static—fixed matrices of common membership (adjacency)—without much information on how the LMOs developed and, just as important, how the adjacencies among legislators emerged. To be sure, this limitation results from the paucity of data on LMOs that extends back beyond five or 10 years, as well as the inchoate nature of network methods for over-time data.

Understanding how LMOs form and how their memberships evolve would permit Ringe, Victor, and Carman, as well as other researchers who follow, to more convincingly distinguish LMOs and their networks as important social entities, rather than as the epiphenomena of preferences or the gaps between other institutions. So, too, if institutional network analysts are to demonstrate plausibly causal or predictive relationships between networks and outcomes, such as legislative productivity and agenda setting (Chapter 7, esp. pp. 198–212) more persuasively, their methods will need to look more like the statistics of “differences in differences.” When changes in LMOs and their network characteristics can be linked, narratively and/or quantitatively, with changes in policy agendas and outputs, the claims of this literature will become more tangible and more credible. A particularly rich research agenda would combine the kind of data aggregated and analyzed by Ringe, Victor, and Carman with the kind of granular narrative and data adduced by Bloch Rubin’s study of the Republican insurgency that led to the Cannon Revolt.

The qualitative elements of the research design present readers with strengths and weaknesses. The in-depth interviews give life to the networks that constitute LMOs and the narratives and data that flow through them. The quotations supplied are telling and specific, and their specificity points to plausible benefits, not least when legislators repeatedly tell the authors that their staff-based research capabilities are so low, or that the exigencies of campaigning (and in the United States, fund-raising) leave no time for in-depth policy research (see especially Chapters 5 and 6). Yet when the authors turn, in Chapter 7, to identifying the different instances in which LMOs plausibly shaped or reshaped policy, the reader (this reader, anyway) pines for an in-depth case narrative that clarifies just how the LMO operated and was influential in changing legislative agendas, behaviors and outcomes. The authors’ treatment of the European Parliament’s Baltic Europe Intergroup, a working group on the Baltic Sea Region, offers one such possibility, but its treatment is threadbare (pp. 187–91), consisting of a stunted time line and a dense table comparing the group’s working paper with an eventual European Parliament resolution.

Other questions surface once we open the doors of the chamber and consider its political ecology of influence. In light of new research by Alexander Fertel-Hernandez suggesting that extralegislative networks supply policymakers with critical information at the state level (“Who Passes Business’s ‘Model Bills’? Policy Capacity and Corporate Influence in U.S. State Politics., Perspectives on Politics 12 [September 2014]: 582–602), is it possible that ideologically aligned (and business-friendly) organizations like the American Legislative Exchange Council (ALEC) could eventually take up some of the functions currently performed by LMOs? Will the tendrils of ALEC become the next infrastructure of a congressional caucus or an insurgent policy bloc within or across parties? If parties are displaced by such arrangements, will they not fight back? Indeed, do LMOs exist only because the parties, committees, and other power players of legislative life think they will not jeopardize their own essential powers and functions? If LMOs eventually start doing “real” work and pose a threat, would parties move in and snuff them out? How would bridging ties help LMOs then? These are questions that the next generation of LMO scholarship, building upon this book, will have to address. And historical perspective and dynamic network analysis will be necessary in doing so.

For now, the authors have set a new standard in the examination of legislative networks, sending the rather lifeless and institutionally disembodied analyses of cosponsorship networks to a distant and well-deserved retirement. Their hypothesis of LMOs as composed of weak ties whose bridging function empowers their performance is a pivotal hypothesis with which the legislative politics literature will now have to wrestle. The future of this important subfield lies in the study of emergence.