We quantify the economic and political effects of removing internal borders within Europe. We develop a spatial model of trade and public service provision in which governments redistribute income, deliver public goods whose effectiveness depends on political alignment, and face border‐related trade frictions. Political alignment is measured from vote‐share‐weighted party positions, yielding a region’s political distance from its central government. The model is calibrated to European regional data on incomes, populations, trade flows, and political preferences. Counterfactual integration eliminates all internal borders, allowing us to decompose welfare changes into contributions from redistribution, trade cost reductions, political alignment, and shifts in the public spending base. The analysis reveals substantial heterogeneity in the regional gains and losses from integration, reflecting spatial differences in both economic and political geography.