In my bicentennial-birthday congratulations to Richard Cobden, I claim  that, because he was one of history’s most successful advocates of free trade, he was one of history’s most successful advocates of civilization.
Trade and civilization are intimately, indissolubly connected. Trade creates civilization. The greater the freedom to trade, the more civilized the society; the more civilized the society, the greater the freedom to trade.
People, to the extent they are civilized, do not forcibly restrict the range of persons with whom others can trade peacefully. People, to the extent that they are civilized, attach no significance to the nationality of those who offer peacefully to trade.
Historian Will Durant (1939 ) penned one of my favorite descriptions of the ultimate benefit of open, free commerce – pointing out that reason itself is a child of open trade:
The crossroads of trade are the meeting place of ideas, the attrition ground of rival customs and beliefs; diversities beget conflict, comparison, thought; superstitions cancel one another, and reason begins.
Put another way, protectionism not only keeps prices unnecessarily high and not only creates unjustified special privileges for the politically powerful few. Most importantly, protectionism breeds ignorance and stupidity, two arch-enemies of civilization.
People, to the extent that they are civilized, find the very notion of protectionism to be barbarous.