Here is the best article I could find on the topic.  If you have not read Piketty&#x27;s book it is a good summary:<p><a href="http:&#x2F;&#x2F;scalar.usc.edu&#x2F;works&#x2F;growing-apart-a-political-history-of-american-inequality&#x2F;index" rel="nofollow">http:&#x2F;&#x2F;scalar.usc.edu&#x2F;works&#x2F;growing-apart-a-political-histor...</a>