Natural allies? Trade unions, social movements and third sector during the economic crisis of 2008 in Spain

This article tests John Kelly's thesis that trade unions and social movements are "natural allies". To this end, it studies the actions of trade unions, 15M and third sector organisations in Spain in the context of the austerity policies promoted by the government after the economic crisis of 2008. After a theoretical review of the relations between trade unions and movements, and the contextualisation of the protests after the 2008 crisis, the article analyses the trade union response to the crisis and the relations of convergence and competition between trade union organisations, civil society organisations and the 15M movement. Subsequently, the trade union strategies of the creation of Mareas and the Social Summit are analysed. The results show that the trade union field and that of civil society organisations contain important fractures and contradictions that give rise to different trade union strategies, which makes it necessary to present some objections and nuances to the natural allies thesis. The article concludes that factors such as trade union traditions, political economy contexts, competition between organisations, and the characteristics of social movements themselves explain the diversity of ways of relating between trade unions and movements, making it necessary to develop more complex approaches that are sensitive to the specificities of each historical and geographical context.