The legitimacy and place in society of trade unionism became a compelling issue in the third quarter of the nineteenth century as the law, economic theory, business practice, and the political system were obliged to accommodate the development of large-scale craft-based trade unions. The mid-century social ‘equipoise’ encouraged a more moderate approach to working-class institutions of all types: the SSA was itself taken to represent a new age of class harmony. The acceleration of popular politics in the 1850s and the extension of the franchise in the 1860s forced both parties to acknowledge the existence of a politically conscious section of the working class, largely associated with trade unionism, and compete for its votes. For their part, unions developed sound internal organisation and finance and institutionalised themselves at local and national levels through the development of trades' councils and the Trades Union Congress. In complex social and political interactions the substantive legal and political achievements of the unions were gained with the acquiescence, if not enthusiastic support, of both political parties. In the process, however, trade unions were encouraged to accept dominant social and economic values. The Social Science Association was prepared to recognise the advance of trade unionism, but it sought leave, in recompense, to impose on the unions a series of expedients for industrial harmony calculated to limit their functions and influence.