That excellent quote in the title is from Kevin Williamson writing in National Review — “Brexit: Deal or No Deal“
The great benefit of trade is the imports, not the exports — the politicians always get that wrong.
Next time someone tells you the opposite, correct them.
For eons, kings, consuls, emperors, and khans undertook enormous pains to keep the trade routes open and to establish new ones, building everything from roads to navies to educational institutions (propagating the once-arcane sciences of accounting and basic finance) to enable the exchange of goods. It is a myth that the Romans salted the fields of conquered Carthage: They ate the grain Carthage grew, and only would have been starving themselves. They needed those imports.
In our time, we have stood that on its head, and as the merchants of the world bring the best of everything to our shores for our use and delight, our biggest worry is that they are not charging us enough money for their goods. These are dumb times.