The political life of Argentina between 1946 and 1955 cannot be defined exclusively by the emergence and consolidation of Peronism, but was also shaped by the actions, ideas and conflicts of opposition to it. The evolution of the Radical and Socialist parties during those years was marked both by their respective internal discrepancies and by the dynamics of confrontation with the government. In the face of Perón's emergence as a political figure, Radicals and Socialists revitalised inter-party agreements that had been tried and tested in previous years. The Radicals, their internal disagreements notwithstanding, were to become the main representatives of anti-Peronism their oppositional roles changing as the institutional spaces for conflict and engagement with Peronism developed. Meanwhile, the Socialists lost political and representational weight, despite their desperate attempts to maintain themselves as an option within the political arena. When the rules of political competition changed in Peronism's favour, Radicals and Socialists became convinced of the legitimacy of challenging the constitutional order in an attempt to increase the political representation of anti-Peronism.