The impact of economic isolation in a global economy is seen in two real world examples:
1. North Korea
2. The “Great” Depression in the US - note that elsewhere it was only called a depression. FDR tried to “protect” American jobs. How did that work out?
Was the Great Depression primarily a result of trade policy? My impression is that FDR let the unions run wild, and established a minimum wage almost immediately after he was elected. These served to price almost a third of the labor force out of the market, because their productivity fell below the wages companies were required to pay. The choice isn't between North Korea-style autarky and completely open trade - it's between South Korea-style managed trade where buyers of foreign goods are subjected to tax audits and open trade.