To each his own

摘要

When Canada, Mexico and the United States implemented the North American Free-Trade Agreement (nafta) in 1994, it was hailed as a promising first step towards the deeper integration of the continent. Six years later Vicente Fox, then Mexico's president, called for a customs union, a common external tariff and free labour flows. And in 2005 the leaders of the three countries began a series of annual summits to push an ambitious "security and prosperity" agenda. Since then the drive for integration has ground to a halt.