The so-called “Southern strategy” of exploiting racial divisions for political gain actually had roots in the urban North in the 1930s and 1940s, according to a new book by James Wolfinger, an assistant professor of education and history at DePaul University in Chicago.

Wolfinger illustrates how racial tensions in working-class neighborhoods and on job sites shaped mid-20th century liberal and conservative politics in his new book, “Philadelphia Divided: Race and Politics in the City of Brotherly Love” (The University of North Carolina Press, 2007). The book provides a detailed study of urban life, race and politics in Philadelphia between the 1930s and 1950s.

“Scholars typically argue that the Republicans began using race to polarize the parties in the 1960s,” Wolfinger said. “But what my book shows is that race became a key component of northern urban politics decades before that.”

As racial divisions fractured the working class, he argues, Republican leaders exploited the division to reposition their party as the champion of ordinary white citizens besieged by black demands and overwhelmed by liberal government orders.

“Philadelphia’s story reveals much about the course of 20th century American politics. By analyzing racial tensions in the workplaces and neighborhoods of ordinary Philadelphians, it demonstrates the limits imposed on liberalism from below,” Wolfinger said. “At the same time, it highlights the ways in which the Republicans reconstructed their party by developing racial politics that portrayed the GOP as the last line of defense for embattled whites. This combination of internal division and external Republican politics shows how liberalism faltered and made way for the Republican Party to construct a cross-class coalition that grew powerful in the second half of the twentieth century.”

By analyzing Philadelphia’s workplaces and neighborhoods, Wolfinger shows how events in people’s everyday lives informed their politics. People’s experiences in their jobs and homes, he argues, fundamentally shaped how they viewed the crucial political issues of the day, including the New Deal and its relationship to the American people, the meaning of World War II in a country with an imperfect democracy and the growth of the suburbs in the 1950s. “This story,” Wolfinger writes in the introduction, “approaches politics from the bottom up, paying careful attention to the everyday lives of the ordinary people of Philadelphia, analyzing how they interacted with each other in their neighborhoods and at their workplaces and how those interactions informed their politics.”

The pivotal chapters of “Philadelphia Divided” explore a racially motivated “hate” strike at the Philadelphia Transportation Company in 1944. Coming just weeks after D-Day, the strike offers a telling example of how Philadelphia’s racial divisions shaped the city’s politics. White workers walked off the job rather than obey an order to accept African-Americans as drivers, and President Franklin D. Roosevelt sent in 5,000 troops to settle the strike. He did so more to maintain war production than to secure jobs for black workers. But many working class whites viewed the government’s use of force as support of black rights and evidence of an alliance between African-Americans and the Democratic Party, and they abandoned the party because of it.

“Roosevelt said, ‘Go back to work or we’ll draft you into the war. Drive a bus or drive a tank,’” Wolfinger said. “Republicans, who had been emphasizing the connections between African-Americans and the Democratic Party for years, used that federal intervention as a lesson to whites of the supposed dangers posed by a liberal government. In the postwar years, the GOP bolstered its power by arguing to white Philadelphians that it could stand up to the black-liberal alliance.”