For Two Economists, the Buffett Rule Is Just a Start

Emmanuel Saez and Thomas Piketty have spent the last decade tracking the incomes of the poor, the middle class and the rich in countries across the world. More than anything else, their work shows that the top earners in the United States have taken a bigger and bigger share of overall income over the last three decades, with inequality nearly as acute as it was before the Great Depression.

See also the graphics:

GRAPHIC: Income Earned by the Wealthiest

GRAPHIC: Who Gains Most From Tax Breaks

GRAPHIC: Whose Tax Rates Rose or Fell

Society can't function well without a minimal sense of national solidarity and cohesion, and that sense of shared purpose also rests on a fair tax system.