This article examines how the redistributive design of crisis-time fiscal policy shaped Belgian federal public debt trajectories from 1912 to 2024. Drawing on a reconstructed debt-to-GDP series and historical–institutional analysis, it identifies a secular transformation in the distributive logic of fiscal adjustment. From 1912 to the late 1970s, broadly speaking, debt surges were addressed through explicitly progressive instruments grounded in the ability-to-pay principle, and on the view that capital should be taxed at least as heavily as labour. From the 1980s onward, this paradigm gave way to a competitiveness-oriented model that eroded tax progressivity, detached capital from the global tax base, and shifted the fiscal burden onto consumption and labour—disproportionately affecting middle-income earners. The evidence presented in this article points to three plausible determinants of this transformation: the role of mass warfare in legitimising progressive taxation; the ideological shift from Keynesian interventionism to supply-side orthodoxy; and the twin constraints of internal federalisation and external Europeanisation. […]