Passport Needed?

Does anyone know if you need a passport to cross into Canada and back? It used to just be a drivers license, but I'm not sure if they've gotten stricter. You used to be able to cross back and forth into Mexico just by stating your country of origin and now you have to have a passport. It takes a thousand times longer to get through the gates these days. You literally stand in line for 2 or 3 hours just to make the crossing. I'm happy for the extra security, but it does take a chunk of time out of your day!