"The No. 1 priority should be NAFTA," said Mark Nantais, president of the Canadian Vehicle Manufacturers' Association, "We should be negotiating these [other] agreements as a NAFTA bloc because of the high integration of our industry.". 

Mr. Nantais doesn't adequately appreciate that (a) the Trump Administration has clearly nixed  US participation in the TPP, & (b) there's a very real chance that the US will withdraw from NAFTA & a near certainty that NAFTA renegotiations (if they continue) will be protracted.

It's in Canada's interest (& Mexico's) to be seen actively negotiating both NAFTA & TPP simultaneously (even though this will be awkward at times). The other countries will not delay matters for our convenience & the danger is that we will lose both NAFTA & the TPP if we try to delay our TPP negotiation participation.