Up until a few years ago, a driver's license was enough to allow
a person to cross the Canadian - U.S. border, but that's no longer true.

I have heard that now if a U.S. citizen goes to Canada without a
passport, just a driver's license, he or she will have difficulty getting back
into the United States. Does anyone know from experience what happens
if you are in Canada and don't have your passport? What happens at the
border? How does such a person ever get back in the U.S.?

Has this happened to anyone here?