An obvious candidate for blame is public policy. The short answer is not really. That answer, though unpopular in the current climate, is yes. Since the greatest movement toward inequality occurred in the 1980s during the Reagan administration, it is tempting to link this problem to the trickle-down economics then espoused by the White House. Tempting, but by and large, inaccurate.
Public policy affects the distribution of income most obviously through tax and transfer policies.
Income and corporate taxes are moderately progressive, while transfer policies are very progressive. To assess how progressive, CBO analysts computed the distribution of income before and after all federal taxes and transfers in 1990, using the Gini coefficient. This coefficient ranges from zero to one, with zero denoting full equality. They found that federal taxes and transfers were moderating inequality by accomplishing substantial redistribution. In 1990, the Gini coefficient before all taxes and transfers were taken into account was .523.