Answer
Peace is needed for an economy to experience its greatest level of consumption. If, instead, the society was at war, then there would be increased production of war-time goods, but then there might be a decreased population in the society for consumption.
Work Step by Step
Taxes allow the government to spend, and a flat tax would be easier to enforce than a tiered tax. With justice, Adam Smith thought the government should step away from commerce and enforce the law.
