Harper apparently sensed that free trade with the US was not a given.  He mentioned what Bush told him about the impossibility of getting a free trade vote in the Congress.  That explained why he repeatedly encourage Canadian businesses to increase capital investment to increase productivity, and his government negotiated quite a few free trade agreement with Europe and a few other countries.

Harper is probably right about this, especially in hindsight.  His latest prediction was the US may just pull out of NAFTA all together.  Let's see how Canadian business react.  If you just look at the stock market, however, the market seems to think NAFTA will stay.  My guess is, even if NAFTA stays, Canada will make a huge concession.  The $800 duty free limit, for example, would devastate Canadian retailers, much in the same way how Amazon destroys the US retailers.