You can currently enter Canada without a passport... but you cannot reenter the US from Canada legally without one- the exception is if you are an illegal alien crossing the southern border. Absurd reality. I’ve applied for permits to enter Canada the last three years in a row at monument marker # 78. That is where the Pacific Crest National Scenic Trail terminus is, and the location is not staffed by either US or Canadian border security agents. The trail continues on for 8 miles into Canada, leading to Manning Provincial Park. Because the crossing point is not staffed, US law prohibits reentry at this point on our northern border.