This Article brings new perspectives on the well-known Viking and Laval cases, decided by the Court of Justice of the European Union (CJEU) in December 2007, by studying the processes and modalities of the construction of this case law as a major defeat for social Europe. It demonstrates that the political and legal implications of these two rulings were socially constructed by a variety of European actors (especially trade unionists and academics specialising in labour law) rather than legally inscribed in the rulings. In doing so, the author defends a constructivist approach in the analysis of European case law, both contextual and processual. The Article is divided into two parts. The first retraces the pre-ruling construction of the Viking and Laval cases, and shows that trade union and academic actors as well as parliamentarians worked to construct the judgements on these cases as decisive landmarks for social Europe. The second part considers the process of interpretation of the rulings after they were delivered by the CJEU. It evidences the central role played by trade union and academic actors in promoting a critical reading of the rulings, arguing that the Court subordinated social rights to economic liberties. The Article concludes by showing that this interpretation has tended to become subject to consensus, to the extent that it is now European common sense.