This thesis aims to analyse how three different instruments of European social policy with different convergence capacity have been implemented in one member state (Portugal) and try to understand the factors that explain the different degrees of change in domestic policies in response to European pressures. The subject of this dissertation emerged from a paradox: Portugal reveals a noticeable capacity to incorporate pressures from European social policies soft mechanisms, but at the same time shows a consistent pattern of bad compliance when it comes to hard-law instruments. This pattern of asymmetrical compliance creates an appropriate setting to understand how on one hand the Europeanization process affects domestic policies, and on the other, which factors explain the variation in the levels of policy change from one sub-field of social policy to another via policy instruments with different convergence capacities. I claim that the reasons for compliance with Europe should be sought in domestic factors, namely in the combination of a conducive context created by a strong European legacy in domestic policies with the convergence between the European pressure and the domestic policy agenda in policy arenas whose characteristics facilitate policy change. I make the case that there is no dualism between a politicisation and a socialisation approach. In fact, even considering the predominance of politicisation mechanisms, I argue that when compliance occurs, both mechanisms are present. My argument is that responses to European pressures reflect not only the introduction of new incentive structures but also the creation of new patterns of social relations. This is particularly true for European social policies, an area where Europe has invested over time in the dissemination of ideational resources, alongside material incentives. I argue that those ideational resources have a delayed effect by formatting policy arenas and giving meaning to certain incentives, providing a social context whereby pressures are perceived both as costeffective and as legitimate. The corollary of this line of reasoning is that there is no relation between the a priori convergence capacity of European policy instruments (i.e. soft and hard-law) and their de facto effectiveness. In the cases analysed, the decisive factor for domestic compliance was the combination of ideational with political factors. Furthermore, I argued that the distinctive traits of each policy arena are central to understand the extent to which EU policy initiatives mobilise domestic coalitions, which prove decisive for the resistance of policy innovation.