My understanding was something like this: sometime in 2006, Canadians would need a passport to enter into the US. Sometime in 2007, Americans would need a passport to return to the US.
I have a hunch that someone will change their mind before this is implemented, and probably at the behest of the Canadian and Mexican governments – why spend $65 to $80 (or whatever they cost now) for a passport just to be able to go back and forth across the border? That’s a lot of money to some people, and people that live on the border don’t really have the attitude that they’re going to a whole new foreign county, i.e., it’s not “tourism” per se, and I suspect that those without passports just won’t bother. <em>This is a huge, huge loss to the Canadian and Mexican economies!</em>. I imagine that American merchants are making a campaign against this, too. In Michigan at the “border malls” all I see are Canadian license plates. At the K-Marts on the Mexican border all I see are Mexican license plates (admittedly not such a big deal; they already need a passport in addition to a visa).
FWIW, I’ve been married to a foreign national since before 911, so I’ve used a passport at every crossing since then. Many times the Americans and the Canadians both don’t even bother to look at the documentation! So it’s still kind of a “how you present yourself” type of being-caught, I think. Prior to using a passport, my experience was always identical to rfgdxm’s at Sault Ste. Marie and Sarnia and Windsor going and coming. Lines were fast moving, too. Now it’s a half-hour ordeal coming back to the 'States, but entering Canada is still relatively quick.