NAFTA can be a double edge sword.
For example, Canada is not allowed to reduce export of Oil to the US. Doesn't sound like much... except the US and Canada have been in a battle over soft wood lumber. It would be nice if Canada could play the same game as the US.
We can. We've won cases in front of WTO and NAFTA panels on this issue and, because the US is refusing to abide by their rulings, we are allowed retaliatory action. Both the right wing of the Federal Liberals (Martinites) and the Conservatives are against such action because they are afraid of angering the US.