We examine whether fiscal consolidation reduces public debt, using local projections difference-in-differences on 126 consolidation episodes in the EU-27 between 1996 and 2024. Entering consolidation raises the debt-to-GDP ratio in the short run rather than lowering it. A decomposition of debt dynamics traces the pattern to a widening interest–growth differential and to stock-flow adjustments that together more than offset the improvement in the primary balance. Two transmission channels sustain the outcome. Output contracts and sovereign spreads rise rather than fall, so no credibility dividend absorbs the adjustment. The effect is not uniform across episodes. Consolidations that protect public investment are associated with better debt outcomes, and the adverse response concentrates in episodes with an unfavourable interest–growth differential. These results qualify the debt-reduction logic behind fiscal consolidation and connect with key elements of the EU's 2024 reformed fiscal framework, notably investment protection and country-specific adjustment paths.