From Revolutionary days through 2004, a majority of Americans fit two criteria. They were white. And they concluded their education before obtaining a four-year college degree. In the American mosaic, that vast white working class was the largest piece, from the yeoman farmer to the welder on the assembly line. Even as late as the 1990 census, whites without a college degree represented more than three-fifths of adults.

But as the country grew more diverse and better educated, the white working-class share of the adult population slipped to just under 50 percent in the Census Bureau’s 2005 American Community Survey. That number has since fallen below 48 percent.

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Still, amid all of this change, whites without a four-year college degree remain the largest demographic bloc in the workforce. College-educated whites make up about one-fifth of the adult population, while minorities account for a little under one-third. The picture is changing, but whites who have not completed college remain the backbone of many, if not most, communities and workplaces across the country.

They are also, polls consistently tell us, the most pessimistic and alienated group in American society.