In reply to Tyler:
I run the office of a consultancy business in Canada. We also have a US office. From a business perspective, particularly delivering services, NAFTA grossly inferior to the EU Single Market. Canada are also in the process of getting bent over bigly by the US, and I'm sure you're well aware of the Boeing / Bombardier shafting that going on too.
Also, if you think that the ECJ is a loss of sovereignty, the US is trying to remove the chapter 19 dispute resolution process, so you'd have to go through the US courts!