The bridge is golden. The opportunity may not be.  Photographer: Justin Sullivan/Getty Images
The bridge is golden. The opportunity may not be.  Photographer: Justin Sullivan/Getty Images

Minneapolis-St. Paul. San Francisco. Chicago. Even Madison, Wisconsin. If you are politically liberal and value relatively high levels of income equality, you might live in one of these quintessentially liberal U.S. cities. Yet all four lurk in the bottom half of the 2014 National Urban League's State of Black America report on income inequality between blacks and whites. Among the many places where black-white income is less skewed are Phoenix, Arizona, Nashville, Tennessee and Columbia, South Carolina.

Nationally, blacks and Hispanics earn less than whites and generally have higher rates of unemployment. But there are significant regional variations. And looking at the Urban League rankings, I couldn't help noticing how many northern liberal cities fared poorly on the racial equality index.

The inequality is sometimes intense. According to 2005-2009 data based on the U.S. Census American Community Survey, which was provided to me by John Logan, a demographer at Brown University, the San Francisco-San Mateo-Redwood City metropolitan area has an astonishing $56,000 white-black gap in household median income. The white-black gap in the Minneapolis-St. Paul-Bloomington metro area is about $40,000.

There is no definitive cause, and explanations vary. Mathew Kahn, an economist at UCLA, e-mailed, "Educated liberals are tolerant people who are willing to live in racially integrated areas even if the minority neighbors are poor. Such liberals are more willing to vote for redistributionist policies and this may attract poor people to collect such transfers."

For an extreme example of rich and poor living cheek-by-jowl, consider New York's 14th congressional district, on Manhattan's Upper East Side. One of the very wealthiest of the nation's 435 congressional districts, it is located 2 miles from New York's 16th congressional district in the Bronx, which is one of the nation's very poorest. As any New Yorker can tell you, however, the cheeks don't necessarily live on the same blocks as the jowls. That 2 miles could just as easily be 200.

Housing prices influence inequality. In the Journal of Urban Economics, Kahn cited resistance to growth and sprawl in liberal California cities such as Santa Monica and Berkeley, evidenced by the issuance of few housing permits, as a driver of high housing costs. Those costs discourage minority middle-class households "who have not built up housing equity (because their parents were unlikely to be home owners)," Kahn e-mailed.

Leah Boustan, another UCLA economist, is researching a book on black migration from the South from 1940 to 1970. "Black migrants were less likely to move to San Francisco and Minneapolis (as well as Boston and Seattle) than to other big cities," she wrote in an e-mail. Those cities, she added, "have concentrations of industries (like high-tech today, and its predecessors) that use high-skilled workers. Black migrants were low-skilled and worked in assembly-based manufacturing and so they didn't move to these locations. My guess is that because black migration was low, blacks never broke into public sector employment (a sector that employs many high-skilled blacks today and offers the lowest black-white wage gap). Furthermore, with low black migration rates, blacks may not have broken into union employment (like high-skilled aircraft manufacturing in Seattle)."

Some of the most segregated cities in the U.S. are above the Mason-Dixon line, including Chicago, Milwaukee, Philadelphia and Detroit. All were destinations for black migration from the South. None have the boutique real estate issues of Santa Monica or the high-tech pedigree of Seattle. So what's their excuse?

"Some of the greatest inequalities are in large Northeastern and Midwestern metro areas that grew very large black populations through the 1970s, often concentrated in inner city ghettos," wrote Logan in an e-mail. "This is certainly a factor. But some places somewhat like that (Allentown, Worcester, Camden, even Providence and Hartford) are at the other end of the distribution. I certainly don't think a city's 'progressive' image is very relevant here -- it is more a question of the history of black labor market incorporation, which varies a lot and keeps changing, especially in the South."

The ultimate reasons may be hard to pin down, but a lot of liberal northern cities have truly lousy track records of fostering black-white economic equality, as well as integrated neighborhoods and schools. "We noticed the same thing," said National Urban League President and Chief Executive Officer Marc Morial in a telephone interview. "That's why we thought the national index might shock and irritate some folks."

(Francis Wilkinson is a member of the Bloomberg View editorial board. Follow him on Twitter.)

To contact the writer of this article: Francis Wilkinson at fwilkinson1@bloomberg.net.

To contact the editor responsible for this article: Zara Kessler at zkessler@bloomberg.net.