In the United States, back during the Great Depression, three simple words animated a grassroots upsurge that would help make the nation the world’s first mass middle-class society: Share the wealth! And the nation did. By the end of the 1960s, the top 1 percent’s share of America’s national income had dropped by more than half. The bottom 90 percent share, meanwhile, had jumped from half the nation’s total income to over two-thirds. Redistribution — via the tax code — drove this dramatic egalitarian shift, as high incomes faced high tax rates throughout the middle decades of the 20th century. But these high tax rates, levies that topped 90 percent on income over $200,000, would have no staying power. The relentless assaults of America’s wealthiest would over time grind them down.