The article addresses the question of the extent to which, and the reasons why, western European trade unions may have privileged the protection of 'insiders' over that of 'outsiders'. Temporary Agency Workers, among whom migrant workers are over-represented, are taken as test case of 'outsiders'. The findings from a comparison of Belgian and German multinational plants show that collective agreements have allowed a protection gap between permanent and agency workers to emerge in Germany, but not in Belgium. However, the weaker protection in Germany depends less on an explicit union choice for insiders than on the weakening of the institutional environment for union representation and collective bargaining. The conclusion suggests that European unions are increasingly trying to defend the outsiders, but meet institutional obstacles that vary by country. This article has three interrelated analytical aims. Firstly, through selected case studies within the same multinational companies affected by the same external pressures, it questions the role of efficiencydriven or rational choice-based explanations for using one extreme form of vulnerable work, namely temporary agency work. The cases illustrate diversity in the organisation of the use of agency labour that cannot be explained by company variables alone and require the consideration of social and political factors. Secondly, the article explores some of these factors by comparing 'most similar' cases, i.e. two neighbouring 'co-ordinated market economies' with similar welfare state models, but where temporary agency workers are subject to very different degrees of protection. The comparison allows to identify the importance of union power and related collective bargaining, and representation systems, and thereby to assess Palier and Thelen's (2010) argument more in depth. Thirdly, we go beyond existing institutional accounts by addressing agency and institutional factors together to tackle the underlying question of the extent to which the unions' role in co-organising dualisation depends on their political choices rather than on the environment they are in.
3The comparative perspective adds to the literature on labour market segmentation and on union responses (Benassi, 2013;Lillie, 2012;Doellgast and Greer, 2007;Hassel 2012), by looking in particular at the implications of power and the influencing factors. We propose to problematize the role of employers and trade unions beyond economic determinism and structural approaches that derive their roles merely from supposedly pre-existing interests. Instead, we pay deeper attention to the socio-political context in which the actors operate and which they concomitantly construct.Thereby, we aim to contribute to debates on social inclusion and dualisation by stressing the crucial role of institutionally situated micro-political games, where actors are strategic 'agents' within a context of power relations.The article is organised as follows. Firstly, segmentation debates are addressed and the rationale of a ...