We study the cohesion within and the coalitions between political groups in the Eighth European Parliament (2014–2019) by analyzing two entirely different aspects of the behavior of the Members of the European Parliament (MEPs) in the policy-making processes. On one hand, we analyze their co-voting patterns and, on the other, their retweeting behavior. We make use of two diverse datasets in the analysis. The first one is the roll-call vote dataset, where cohesion is regarded as the tendency to co-vote within a group, and a coalition is formed when the members of several groups exhibit a high degree of co-voting agreement on a subject. The second dataset comes from Twitter; it captures the retweeting (i.e., endorsing) behavior of the MEPs and implies cohesion (retweets within the same group) and coalitions (retweets between groups) from a completely different perspective. We employ two different methodologies to analyze the cohesion and coalitions. The first one is based on Krippendorff’s Alpha reliability, used to measure the agreement between raters in data-analysis scenarios, and the second one is based on Exponential Random Graph Models, often used in social-network analysis. We give general insights into the cohesion of political groups in the European Parliament, explore whether coalitions are formed in the same way for different policy areas, and examine to what degree the retweeting behavior of MEPs corresponds to their co-voting patterns. A novel and interesting aspect of our work is the relationship between the co-voting and retweeting patterns.
Whatare the relational dimensions of politics? Does theway that people and organizations are connected to each other matter? Are our opinions affected by the people with whom we talk? Are legislators affected by lobbyists? Is the capacity of social movements to mobilize affected by the structure of societ al networks? Powerful evidence in the literature answers each of these questions in the affirmative. However, compared to other paradigmatic foci, political science has invested tiny amounts of capacity in the study of the relevance of networks to political phenomena. Far more attention has been paid to the psychology of howpeople process information individually as opposed to collectively, and to the role that institutions play in structuring politics as opposed to the relational undergirdings of politics. A review of the flagship journals in political science reveals a dearth of articles on networks. Few, if any, doctoral programs include courses for which the primary focus is network-related ideas, and even the notion of a relational dependence in data is rarely mentioned in discussions of the assumptions embedded in the statistical methods that dominate political science. This gap is arguably the result of the boundaries among social sciencedisciplines thatemerged inthe1950s,whensocial networkideasfoundtheirhomelargely insociologyandanthropology while political science leaned toward statistical methods that assumed away interdependence among observations. Ironically, there is now awave of interest in networks in political science thathasoriginatedpartly in sociologyandpartly in thatmost distant of disciplines frompolitical science, physics. The objective of this article is to provide an intellectual history of the study of social networks and political networks in particular, as well as the current trajectory of such work.  We analyze the network of relations between parliament members according to their voting behavior. In particular, we examine the emergent community structure with respect to political coalitions and government alliances. We rely on tools developed in the Complex Network literature to explore the core of these communities and use their topological features to develop new metrics for party polarization, internal coalition cohesiveness and government strength. As a case study, we focus on the Chamber of Deputies of the Italian Parliament, for which we are able to characterize the heterogeneity of the ruling coalition as well as parties specific contributions to the stability of the government over time. We find sharp contrast in the political debate which surprisingly does not imply a relevant structure based on establised parties. We take a closer look to changes in the community structure after parties split up and their effect on the position of single deputies within communities. Finally, we introduce a way to track the stability of the government coalition over time that is able to discern the contribution of each member along with the impact of its possible defection. While our case study relies on the Italian parliament, whose relevance has come into the international spotlight in the present economic downturn, the methods developed here are entirely general and can therefore be applied to a multitude of other scenarios. Network theory provides a powerful tool for the representation and analysis of complex systems of interacting agents. Here, we investigate the U.S. House of Representatives network of committees and subcommittees, with committees connected according to "interlocks," or common membership. Analysis of this network reveals clearly the strong links between different committees, as well as the intrinsic hierarchical structure within the House as a whole. We show that network theory, combined with the analysis of roll-call votes using singular value decomposition, successfully uncovers political and organizational correlations between committees in the House without the need to incorporate other political information. We study the United States Congress by constructing networks between Members of Congress based on the legislation that they cosponsor. Using the concept of modularity, we identify the community structure of Congressmen, who are connected via sponsorship cosponsorship of the same legislation. This analysis yields an explicit and conceptually clear measure of political polarization, demonstrating a sharp increase in partisan polarization which preceded and then culminated in the 104th Congress (1995–1996), when Republicans took control of both chambers of Congress. Although polarization has since waned in the U.S. Senate, it remains at historically high levels in the House of Representatives. ABSTRACTMembers of the European Parliament (MEPs) struggle to connect with European publics. Few European Union (EU) citizens feel connected to their MEPs. Levels of turnout for European Parliament (EP) elections are low, and EU citizens rarely retain EP-related news. For these and other reasons, we might expect MEPs to embrace social media platforms, like Twitter, that facilitate interactivity, spontaneity, personality, and informality. In reality, however, significant variation characterizes the timing and nature of MEPs’ engagement with Twitter. In this article, we document and seek to explain elements of this variation. We examine five dimensions of MEP engagement with Twitter: Do MEPs establish Twitter accounts? Are they early adopters? How frequently do they tweet? And how, exactly, do they use Twitter – do they engage in direct conversations via Twitter's @-reply functionality and or refer followers to other content via retweeting? We find that MEPs’ approaches to Twitter are conditioned by specifi...