While Canada can & should seek to build its trade & trade pacts with Asia, Europe, & Latin America regardless of whether the US chooses to withdraw from NAFTA, Canada (because of its deep economic integration with the US economy & a likely desire in both Canada & the US to minimize the areas of potential trade dispute in a post-NAFTA arena) may well be inclined to 'go slow' on initiatives to diverge from those economic policies we share with the US.  

We see something similar in UK  plans for Brexit. Even though one of the strong emotional motivations for leaving the EU during the referendum campaign was to reassert Parliament's jurisdiction over many areas of US public policy, many of the most hardcore Brexiteers now advocate that the UK adopt EU policies to maintain economic integration in a post-Brexit world.

Similar debates would arise in Canada.