2012 Decoded

DES MOINES, Iowa -- Rick Santorum would face formidable challenges in converting even a strong Iowa showing Tuesday night into a full-scale national challenge to restored GOP front-runner Mitt Romney. But with a working-class style and message, Santorum could have one weapon: the changing demography of the Republican electorate.

The growing blue-collar presence in the Republican primary could offer Santorum a base from which to challenge Romney because the former Massachusetts governor has not demonstrated a consistent appeal to those voters. In surveys, Romney, the unruffled Harvard Business School-educated former investment banker, has frequently attracted slightly more support from Republicans with a college-degree than those without one.

That could leave a downscale opening for a potential rival -- if anyone can consolidate that blue-collar block against him. "That's the issue," says Whit Ayres, a Republican pollster working with a super committee supporting former Utah Gov. Jon Huntsman.

The changing nature of the GOP primary electorate reflects the overall shift in each party's coalition over the past generation -- a process I've called the "class inversion." In the first decades after World War II, every Democratic presidential nominee ran much more strongly among white voters without a college-education than whites with at least a four- year degree. But, particularly as non-economic issues from racial integration to abortion grew more important, the parties have switched positions. In each presidential election since 2000, the Democratic nominee has run better among college-educated whites than non-college whites; meanwhile working-class white families have become the cornerstone of the Republican electoral coalition.