Antagonism towards global trade imbalances has become a big political issue, from US-China relations to the Euro Zone. Are trade imbalances appearing because some countries are just more responsible with their money than others? Do they have such productive industry that they just keep selling more to foreigners? Matt Klein, co-author with Michael Pettis of the recent book "Trade Wars Are Class Wars," discusses how distributional imbalances within countries manifest themselves to appear as trade wars between countries.