I believe the trading relationship between Mexico, Canada, and United states would be the one that most impacted.
The existence of NAFTA allows better movement of Factors of Production between the three nations. Dissolving NAFTA would most likely increase the import/export tax between this nations and could also lead to the dissolvents of many jobs.
the two factors are inertia and gravity
One such sentence would be this: "The compass was a vital piece of technology that allowed sailors and explorers of all kinds find their position in the world relative to the North Pole".
Their roads and stable infrastructure were the primary reasons that they were able to control such a large empire
