Upvote:3
According to the U.S. Department of State's information on visiting Canada, the only restriction on passport expiration for visiting Canada is that the passport must be valid at the time of entry. That page also lists the contact information for the U.S. Embassy in Ottawa. It might not be a bad idea to either shoot them an e-mail or give them a call just to make sure they don't think you'll get hassled at the border, since 1.5 weeks is cutting it very close as passports go.