Over the last 20 years the trade literature repeatedly documented the trade-reducing effects of inter- and intra-national borders. Thereby, the puzzling size and persistence of observed border effects from the beginning raised doubts on the role of underlying political borders. However, when...

A significant body of empirical studies demonstrates sizable national border effects in foreign trade of Canadian provinces throughout the 1980s and 1990s. This paper revisits and expands the scope of the border effects analysis by estimating the border effect in trade with U.S. states as well...