The bilateral trade flows between Canada and the U.S. are the world's largest and have grown rapidly in the 1990s. Are they evidence of a North American trading bloc? A gravity model of trade finds that while economic size and proximity can explain much of the substantial trade between Canada...

In the late 1980s, Canada's provinces traded 20 times more with one another than with U.S. states of comparable size and distance. In other words, the Canada-U.S. border exerted a strong effect on the pattern of Canada's continental trade patterns. Since then, globalization and the formation of...