MR. PIKETTY, CALL YOUR OFFICE:

For those in Washington obsessed with reducing income inequality, the standard prescription involves raising taxes on the well-to-do, increasing the minimum wage, and generally expanding government benefits—the policies characterizing liberal, blue-state governance. If only America took a more "progressive" approach, the thinking goes, leaving behind conservative, red-state priorities like keeping taxes low and encouraging business, fairness would sprout across the land.

Among the problems with that view, one is particularly surprising: The income gap between rich and poor tends to be wider in blue states than in red states. Our state-by-state analysis finds that the more liberal states whose policies are supposed to promote fairness have a bigger gap between higher and lower incomes than do states that have more conservative, pro-growth policies.