Free trade agreements carry an inherent imperative toward regulating and harmonizing more and more activities within each of the countries party thereto.
In their quest for successively ever more level playing fields, there is a natural tendency for free traders to inevitably seek to harmonize not just explicit tariff rates, but tax systems, labor laws, environmental regulations and any other differences in internal law that tends to confer an advantage on businesses in one jurisdiction over those of another.
We have seen this in the EU, as it has advanced progressively over the years from a coal and steel union centured on the Ruhr to a European-wide federal government, and the forces that produced NAFTA are pushing in the same direction, though we are at a much earlier stage of the process.
If an elected government can't do what voters expect because of international "agreements" (in our case equivalent to unconstitutional treaties), democratic representation has then become a virtually meaningless exercise meant only for public mollification, nor is there transparency in these unaccountable international bureaucracies subject only to the whims of "stakeholders."
I like to call it, "Highly Organized Crime."