Tear down this wall: on the persistence of borders in trade

Why do borders still matter for economic activity? The reunification of Germany in 1990 provides a unique natural experiment for examining the effect of political borders on trade. With the fall of the Berlin Wall and the rapid formation of a political and economic union, strong and strictly enforced administrative barriers to trade between East Germany and West Germany were eliminated completely within a very short period of time. Remarkable persistence in intra-German trade patterns along the former East-West border suggests that border effects are neither statistical artefacts nor driven by administrative barriers to trade, but arise from economic fundamentals.