CTV says the Obama campaign has contacted the Canadian embassy to tell them not to worry about their protectionist rhetoric for the Ohio primary. Obama and the Canadian government both deny it, although apparently there was some sort of chat.
The Pithlord is not in a position to shed light on such backroom dealings. However, I do know that serious environmental and labour standards in NAFTA are not going to fly. Among the reasons is that most environmental and labour law in Canada is within provincial jurisdiction and, unlike in the US, there is no way for the Feds to require provinces to meet international commitments. This is the result of a Privy Council decision that made all my profs at U of T gnash their teeth, but nonetheless remains the law.