The Dawn of PR is just a good starting point. You can read Machiavelli or study the politics of the roman empire - all hierarchical societies tend to function like this, it's a like a mathematical distribution.

The New Deal along with social democracy in europe was a bargaining deal against the revolutionary forces existing at the time. After this was stamped out the Gini coefficient started to rise when the masses had no alternatives and global trade and outsourcing increasingly obscurred the falling realwages.