During the same period, the proportion of affluent families grew from 22 to 27 percent–while the percentage of poor households swelled from 23 to 31 percent. In short, Milwaukee’s middle class families went from a plurality to its smallest minority.

The biggest culprit is the disappearance of well-paying manufacturing jobs. Despite a promising recent uptick in high-end manufacturing, Milwaukee has suffered a 40 percent decline in manufacturing jobs since 1970, when Schlitz, Pabst and American Motors reigned. Instead of shrinking, the city’s urban poverty is creeping outward toward suburbs.

Late Wednesday afternoon, that was evident in the Jefferson Elementary school of West Allis, a once solidly middle class suburb bordering Milwaukee. In a crowded school gymnasium, principal Shelly Strasser said that fifty percent of students now qualify for free or reduced price school lunch programs. In other local schools, the number is ninety percent.

“It breaks your heart,” said Strasser, a West Allis native who said she now has homeless students. “That’s something we’ve never seen as a district.”

The change also emerges in Cudahy, a once middle class suburb just south of the city. As a child, Debby Pizur watched traffic jams form on local streets during factory shifts changes. Today, many of those factories are shuttered, Pizur works three jobs at the age of 59, and runs a non-profit that provides food, clothing and household items to the community’s poor.

The number of families served by her center, “Project Concern,” has doubled since she took over five years ago. Increasingly, families are “doubling and tripling up,” she said, with parents, siblings and children moving in with one another.

“I have no job,” said Brenda, a woman who declined to give her last name and blushed as she picked up free food and clothing. “I haven’t had a job for three years.”

Milwaukee’s poor, meanwhile, are poorer. A drive through the north side district of Alderman Ashanti Hamilton showed it. In the 1970s, the area was home to one of the most prosperous black communities in the nation. Two massive factories employed 15,000 workers.

“In those days, you could lose a job in the morning,” recalled Joe Bova, a 69-year-old retired crime victim advocate. “And have another job after lunch.”

Today, both plants have closed, run-down shops line derelict streets and Ashanti puts the unemployment rate for young black males at 50 percent. In Milwaukee’s poorest corners, the infant mortality rate is higher than that of the Gaza Strip, Colombia and Bulgaria.

All the while, Milwaukee’s wealthier suburbs thrive. Ozaukee County, just north of the city, is the 25th wealthiest in the United States in terms of per capita income.

“It’s basically two cities,” said Howard Snyder, executive director of the Northwest Side Community Development Corporation, a local non-profit. “Now, everybody is locked in. You can’t move in. You can’t move out. You’re stuck. There was a moment for bold action but it has passed.”

Unfortunately, Milwaukee’s dwindling middle class is part of a national trend. A November study by researchers at Stanford University found that the share of American families living in middle class neighborhoods in the United States dropped from 65 percent in 1970 to 44 percent in 2009. Milwaukee experienced the second greatest decrease in the country, according to the study; only Philadelphia’s was worse.

“Income inequality grew,” said Sean Reardon, the author of the study. “The growth in the tails in Milwaukee and the shrinking middle class is what I’d expect to see.”

How to slow that trend vexes Milwaukee officials. In the wake of big-government, anti-poverty initiatives in the 1960s and 1970s, Milwaukee adopted market-oriented downtown development projects in the 1990s and 2000s. Today, the city’s center and lakefront boast high-end residential condominiums, a sparkling convention center and stunning Santiago Calatrava-designed art museum.

New service jobs dominate the economy, but vary vastly in pay. As in other American cities, bankers, lawyers and professionals earn handsomely. Cashiers, janitors and restaurant workers struggle to make ends meet.

In recent years, the city turned several abandoned factories into new industrial parks. Tenants range from a local frozen pizza producer to a Spanish-owned firm that manufactures wind-turbine generators. Several thousand new jobs have been created, but the tens of thousands of well-paid, manufacturing jobs that built Milwaukee have not been replaced.

“You had the war on poverty and then you had the trickle down theory,” said Sherrie Tussler, executive director of the Hunger Task Force, a local non-profit that feeds a growing number of formerly middle-class families. “And neither one worked.”

Finding a third way in Wisconsin, an epicenter of American political polarization, will not be easy. Hamilton, the alderman, insists the answers to America’s woes will emerge at the local, not state or federal level.

“It’s happening,” he said. “And it’s been demonstrated that things can work when things are not so politicized.”

The 38-year-old Milwaukee native insists he and other Democrats work closely with local business leaders to try to revive the city. Government alone is not the answer, he said. Nor is the free market alone. Wisconsin, Hamilton insists, is an example for a divided country.

“It’s an example of what not to do,” he said, “and what can be done.”

I pray he’s right.