The purpose of the thesis is to understand the role of the army in the management of civil conflicts within the 'democratic' republican system in France and the 'semiabsolutist' and 'militaristic' Prussian system. In both countries, existing interpretations of the domestic role of the army focus on legal-constitutional perspectives, governmental and parliamentary policy making, and social conflicts, and are often normative. However, the lack of a cross-national comparative perspective has led to a series of conclusions that are called into question when the French and Prussian cases are compared. The thesis seeks to answer the question why the authorities in French and Prussian industrial areas, when confronted with similar challenges from mass protest movements between 1889 and 1914, adopted strategies that involved very dissimilar roles for the army in maintaining public order. On the basis of empirical observations of the process of bureaucratic decision making and inter-institutional co-operation between the state administration and the military authorities in Westphalia and Nord-Pas-de-Calais, the analysis was established using a 'historical institutionalist' framework of interpretation. The thesis puts forward two main arguments: that the strategies adopted by the French and Prussian authorities in the early 1890s that involved very dissimilar roles for the army in domestic peacekeeping were linked to dissimilar perceptions of the threat to the regime. The French Republic, despite its democratic and civilian ideals, made extensive use of the army because the fragility of the regime meant that it could not afford the danger that public unrest might get out of control. Conversely, the Prussian authorities considered their regime to be sufficiently stable to experiment with strategies to deal with public unrest that did not imply military intervention, even if these strategies provided a much lower degree of control over public unrest. The other main conclusion of the study is that the repeated implementation in the French case o f strategies that involved mobilisation of the army and the implementation in the Prussian case of strategies that drew upon civil forces alone, led to different strategies, organisations and uses of forces available. Hence, veiy dissimilar patterns of inter-institutional co-operation developed between the state administration and the military authorities in Westphalia and Nord-Pas-de-Calais.