<P> Liberal political scientist Larry Bartels has found a strong correlation between the party of the president and income inequality in America since 1948 . (see below) Examining average annual pre-tax income growth from 1948 to 2005 (which encompassed most of the egalitarian Great Compression and the entire inegalitarian Great Divergence) Bartels shows that under Democratic presidents (from Harry Truman forward), the greatest income gains have been at the bottom of the income scale and tapered off as income rose . Under Republican presidents, in contrast, gains were much less but what growth there was concentrated towards the top, tapering off as you went down the income scale . </P> <P> Summarizing Bartels's findings, journalist Timothy Noah referred to the administrations of Democratic presidents as "Democrat - world", and GOP administrations as "Republican - world": </P> <P> In Democrat - world, pre-tax income increased 2.64% annually for the poor and lower - middle - class and 2.12% annually for the upper - middle - class and rich . There was no Great Divergence . Instead, the Great Compression--the egalitarian income trend that prevailed through the 1940s, 1950s, and 1960s--continued to the present, albeit with incomes converging less rapidly than before . In Republican - world, meanwhile, pre-tax income increased 0.43 percent annually for the poor and lower - middle - class and 1.90 percent for the upper - middle - class and rich . Not only did the Great Divergence occur; it was more greatly divergent . Also of note: In Democrat - world pre-tax income increased faster than in the real world not just for the 20th percentile but also for the 40th, 60th, and 80th . We were all richer and more equal! But in Republican - world, pre-tax income increased slower than in the real world not just for the 20th percentile but also for the 40th, 60th, and 80th . We were all poorer and less equal! Democrats also produced marginally faster income growth than Republicans at the 95th percentile, but the difference wasn't statistically significant . </P> <P> The pattern of distribution of growth appears to be the result of a whole host of policies, </P>

Reasons for income inequality in the united states