Klein and Pettis argue that global trade tensions are not really about countries fighting over exports, but they are the result of deep inequality within countries. When income is concentrated among elites, ordinary people cannot afford to buy what they produce, so economies like China and Germany end up exporting their surplus goods abroad. This creates trade imbalances and fuels economic nationalism, especially in countries like the US that absorb these surpluses. The authors show how domestic class conflict (where workers lose out and the wealthy save excessively) drives international financial instability. Their core message is that fixing trade wars means first addressing inequality at home, through policies that boost wages, consumption, and public investment.