But the thing is, if we completely cut off trade, or even halve it, that could be millions out of jobs. 4.3% job loss out of 1.3 Billion people is about, if my math is correct, is about 58 MILLION people jobless.
Not really. We import far more stuff than we export on a dollar-for-dollar basis, even with the "benefit" of the stuff made overseas is cheaper than if it was made here. If we cut off all trade of manufactured goods with other nations (and used whatever means necessary to ensure supply of raw materials), and just started making stuff here again, prices would skyrocket but we'd see very low unemployment.
Yes, the standard of living for the average low-skill worker would probably drop since your average broomstick maker would no longer be able to afford that 52" plasma and a new car every 3 years, but they'd have plenty to eat and wear and would probably be healthier overall since expensive tech gadgets and super-cheap foods contribute to America's obesity problem. A little more time spent doing cheap or free leisure activities instead of plopping down in front of the tv would technically "lower the standard of living", but people would be a hell of a lot more healthy.
So cutting off all trade of manufactured goods... Non-essentials would be a lot more expensive but we could make everything we need right here and use whatever means necessary to procure raw materials (what good is an expeditionary military if you don't USE it, eh?). And maybe we'd actually benefit from the use of our military instead of just using it to whomp on people who are already perfectly happy beating on each other without our help.