Given New Republic's political bias, you should understand its concern is how to reclaim the votes of the white working class (those with less than a 4 year college degree) for the Democrats. Author Andrew Levison maps voting patterns by region (see map), and finds:
White working class support for Obama in 2012 was at or below an abysmal 30-31 percent not just the South but in large areas of the country that include the “rural heartland” of the Midwest and far West, the Mountain West, and the Southwest.The other issue Levison examines is where people live on a urban to rural continuum.
Today, two-thirds of white workers live in small towns, the urban fringes around metropolitan areas, or rural areas; only a third remain in central cities or suburbs.Levison concludes:
White working class support for Obama declines as one moves from large metro areas to less urban settings.
The party could "write off" white working class in the South and still win many elections, but it's impossible to write off working Americans in all of the Red States or in all non-urban areas and still have a stable and enduring Democratic majority.His findings fit with my observations as a rural resident. Hat tip to RealClearPolitics for the link.