["Economic Inquiry, Volume 64, Issue 2, Page 681-701, April 2026. ", "\nAbstract\nWe build an endogenous growth model that distinguishes productive and welfare government expenditures and embeds fiscal externalities. The model yields three testable hypotheses: (i) productive expenditure raises growth (Barro effect); (ii) productive expenditure generates cross‐country productivity spillovers; (iii) government expenditure structure exhibits spatial dependence. Estimation with a spatial‐panel dataset for 30 European economies (EU27 + 3) corroborates all three hypotheses. We further show that positive productivity externalities induce an international free‐rider problem, causing systematic under‐investment in productive expenditure, while negative welfare externalities trigger a “welfare tournament” and over‐spending on non‐productive expenditure.\n"]