Socio-economic rights are ethico-political claims to employment, social security, health, education and adequate living standards, the understanding and contestation of which have changed over time. In this article, I examine the first wave of attempts to constitutionalize socio-economic rights in Mexico (1917), Weimar Germany (1919) and, in particular, the Irish Free State (1922). The real politics of constitutionalizing socio-economic rights, I argue, centred on a clash between popular, anti-systemic movements and governments’ attempts to contain the ideals and practices of these movements. In all three cases, escalating popular militancy spurred state constitution makers into proposing socio-economic rights as an alternative to revolution. In the Irish Free State, however, the ruling class’ successful containment – militarily, politically and ideologically – of social movements’ ideals and practices ensured more conservative constitutional forms predominated, emphasizing national identity and private property rights. The critical discourse analysis of the Irish constitution-making process demonstrates the salience of both ‘national’ (core–peripheral) and ‘social’ (capital–labour) relations in determining final constitutional forms of socio-economic rights. For socio-economic rights advocates and scholars today, these findings invite fresh reflection on the limits of claiming rights from the state in a capitalist society.