> You're not entirely wrong. There is a cost to duplicating effort. What is the cost of not being independent? Your country's sovereignty and maybe your life. L

> You're not entirely wrong. There is a cost to duplicating effort. What is the cost of not being independent? Your country's sovereignty and maybe your life. Let us take care of ourselves as best we can and import only a small amount of stuff. At what scale does that become true? Certainly an individual is not better off importing as little as possible? This would mean not working any traditional job, not buying tools, not buying food, but crafting a comfortable life on one's own starting naked and with bare hands. Certainly it doesn't make sense to apply such a policy to the individual. Should cities then be the scale at which this cutover happens? If a natural resource does not appear in its geography the citizenry must do without? Every city farms all of its own food, has factories for all told and merchandise its citizens wish for? Cars, industrial equipment, forestry, mining, clothing, food, technology, all made within the city limits? There is not even enough room for all of this. A US state? A small country? What is the cutover point at which one is not impoverished by such a policy? Or perhaps you believe I take too extreme a position on protectionism and think some trade is good at any scale. The same threshold must exist: If it improves our well being to trade a little, what is the threshold at which more trade stops making us better off? Where is the inflection point at which a bit more trade hurts us? Can you point us to a country with an optional amount of trade? Or could you compare two countries based on their amount of trade and tell us which is better? If you prefer a different framing: hopefully we can agree that isolationism at the level of North Korea is a negative for its citizenry, independent of the dictatorial regime they live under. It seems that you believe the US trades too much. So we can imagine a curve of some sort on a graph with the US on the left end and North Korea on the right. The slope moving from US starts off positive. The slope moving from North Korea starts negative. Somewhere between the two, there must be a maximum. How would one calculate it?