It's why Perdue's remark was so costly. He wasn't just mocking Handel; he was mocking many of the very voters whose support he wants during the May primary. Sarah Palin, whose anti-elitist message best personifies the party's working-class turn, summed up the feelings of many Republican voters when she campaigned for Handel last month: "There are a lot of good, hard-working Americans who have more common sense in their pinky finger than a lot of those Ivy League pieces of paper up on a wall."

The problem for some Republican candidates like Perdue, the former CEO of Reebok and Dollar General, is that many of them still hail from the party's managerial ranks. And that leaves them on unsure footing as they try to communicate with a base whose experiences and outlook are fundamentally different than their own.

That tension is one its White House hopefuls will have to navigate carefully ahead of the 2016 primary.

"Ten years ago a Republican primary was decided by who has the best resume," said Joel McElhannon, an Atlanta-based GOP strategist. "Having broader experience was considered a big plus, but we've seen this shift over the last several years. There is this populist strain going through the Republican primary electorate, and now it's less about experience and it's more about being an outsider. It's less about being qualified than who is more angry and more likely to ruffle feathers."

The two political parties have essentially traded places over the last few decades. Democrats, who once depended heavily on blue-collar workers, have become increasingly the party of white-collar workers, at least among whites. And as downscale whites leave the Democratic Party, they've joined the GOP, whose cultural values often align with their own.

"Blue-collar whites have been migrating to the Republican Party ever since Ronald Reagan called them Reagan Democrats," said Whit Ayres, a Republican pollster. "It's a culture that is heavily family based, more small-town and rural. It's very pro-gun, and very patriotic. We're talking about a group of folks who see Democratic efforts at gun control as a cultural assault, an attack on their values."

They played a pivotal role in the 2012 Republican primary, prolonging Mitt Romney's ascendancy to the nomination long after most of his backers would have liked. In the critical early state of South Carolina (where Newt Gingrich won), voters without a college degree made up 53 percent of the electorate, according to exit polls. In Ohio (where Romney barely held off Rick Santorum), they constituted 55 percent of the electorate. Iowa's caucus was 48 percent blue-collar.

Romney won the nomination despite his private-equity background and numerous cringe-inducing gaffes—like saying his friends were NASCAR team owners or challenging Rick Perry to a $10,000 bet. But in 2016, the competition among potential candidates like Rand Paul, Scott Walker, Bobby Jindal, and Marco Rubio will be stiffer for every vote.