From the Globe and Mail:
The U.S. government has confirmed what many Canadian officials and business people have long feared that the economic burden of the border-passport requirement will weigh more heavily on Canada than on the United States.
Washington says its plan to require passport-like documents on cross-border traffic beginning in 2008 will have â€Ŕmarginal†impact on the United States because it expects more Americans to spend their travel money at home, and estimates that much of the measure’s negative impact will fall on businesses outside the country.