The thesis discusses the trajectory of the Belgian socialist thinker and activist Hendrik de Man (1885-1953) between 1914 and 1936 ca, with particular attention to his endeavours to renew Western European social democracy after the Great War. The first half of the thesis deals with de Man’s theoretical evolution. Having become convinced of the inadequacy of orthodox Marxism as a conceptual framework for the Left while serving as soldier and diplomat during WWI, de Man sought to overcome the split between reformism and revolutionary socialism by developing an ethical conception of socialism outlined in the book Zur Psychologie des Sozialismus (1926) and, subsequently, by elaborating planism, a democratic socialist ideology supposedly more in tune with the socio-economic conditions of the 1930s. The second half of the thesis focuses on efforts to put de Man’s ideas into practice. Due to his mounting desire to have impact on the social democratic movement, de Man became increasingly involved in politics and, in late 1933, launched the Belgian Labour Plan with the aim of bolstering the Belgian Labour Party and containing the spread of fascism. Planism won support from many young socialists all across Europe but was also met with suspicion and outright hostility by wide segments of the social democratic establishment, including prominent leaders such as Emile Vandervelde and Léon Blum. Eventually, de Man accepted to compromise on the full implementation of the Labour Plan and sought to accomplish the same goals by serving as Minister, without success. By examining his failure as well as the difficulties experienced by his followers in France and Britain, the thesis highlights the limits that Western European social democratic parties set to their own ideological renewal during the interwar period.
Tommaso Milani (Sun,) studied this question.