“What’s happening in cities can be described as Obama’s agenda trickling down to the jurisdictions where it has enough political support to be enacted — but it’s also the incubation of policies and practices that will trickle up,” Meyerson writes. “With considerable creativity and limited power, the new urban regimes are seeking to diminish the inequality so apparent in cities and so pervasive nationwide. They are mapping the future of liberalism until the day when the national government can bring it to scale.”

While Meyerson’s political and demographic data is on target, and he accurately describes a movement toward more redistributive policies, there are reasons to be cautious.

First and foremost, a number of the cities Meyerson points to have exceptional, built-in advantages: major research universities; financial and high-tech corporate centers; substantial and strong artistic and intellectual communities. Pittsburgh, for example, has Carnegie Mellon, metropolitan Boston has Harvard and M.I.T., Seattle has Microsoft and Amazon, and New York has its own varied, almost endless resources.

These advantages are the exception, not the rule. Just ask the residents of Peoria, Trenton, Camden, Detroit, St. Louis, Baltimore, Birmingham or Modesto.

There are clear differences in the resources of these eight cities and the six cities cited by Meyerson. The per capita incomes in the six listed by The American Prospect average $33,200 annually, 57 percent higher than the $21,200 annual per capita income in the less affluent eight. Equally important, the median value of owner-occupied homes in The American Prospect six averages $319,800, 147 percent more than the median home value of $130,200 in the eight struggling cities, according to Census Bureau data.

Another way to look at this is that it takes money and resources to become a liberal city. “You can’t be a progressive without prosperity,” Bruce Katz, director of the Brookings Institution’s metropolitan policy program, said in a phone interview.

In their book, “Toward a 21st Century City for All,” John Mollenkopf, a professor of political science and sociology at CUNY, and Brad Lander, a Brooklyn city councilman who represents Cobble Hill, Park Slope and Boro Park, acknowledge the disparity favoring already successful cities. Mollenkopf and Lander support many of the policies cited by Meyerson and point out that New York is unique in its ability to enact such policies because of its “competitive advantages,” which are “not available to the many declining cities of the United States.”