Democrats suffered their biggest losses last year in blue-collar territory, as Obama's approval ratings with blue-collar white voters plummeted. White voters without a college education voted for Republican House candidates nearly 2 to 1, according to last year's Edison Research exit poll. The party's bulwark of Blue Dog Democrats, many of whom had held onto seats in deeply conservative districts no matter the political climate, collapsed.

While Democrats aren't going to win back many of those seats given the districts' conservative orientation, they're betting that a message decrying income inequality can put some of them in play.

Republicans still hold a healthy edge in support among white voters without a college education--47 percent to 34 percent, according to the latest United Technologies/National Journal Congressional Connection Poll. But their advantage has narrowed significantly since 2010, when they led 63 percent to 33 percent in exit polling. The GOP agenda of spending cuts and entitlement reforms isn't a natural sell with this constituency, which has been hard-hit by the recession.

The Democrats' ability to win back a House majority may well lie with candidates like Brendan Mullen, an Iraq veteran who's running in a working-class, solidly Catholic battleground district in northern Indiana. He's pro-gun and anti-abortion rights, but identifies with the Democratic Party's traditional connection to the working class. Mullen is a convincing representative of the public mood because his biography is authentic to the message he's preaching. He grew up in South Bend and worked for his father's unionized lumberyard, moving Sheetrock and handling deliveries. He attended West Point, went to Army Airborne School and Ranger School, and served in Iraq during the war. He's running for office for the first time.

Mullen is running for the seat being vacated by Rep. Joe Donnelly, D-Ind., one of the few targeted Democrats to survive the 2010 wave. Republicans redrew the lines this year to make the district more favorable for them, but Obama still would have narrowly carried it. Mullen is expected to face Donnelly's 2010 Republican challenger, former state representative Jackie Walorski, an outspoken tea party supporter. If the tide has changed in the Democrats' favor, Mullen should have more than a fighting chance.

Even more than the Massachusetts Senate race, the Indiana contest is shaping up to be a referendum of whether working-class voters identify more with the Occupy Wall Street movement or the tea party. Mullen has close ties to labor and said he feels a connection with the protests taking place across the country.

"The middle class are the ones getting left empty-handed as Wall Street and corporations are getting shored up," Mullen said in an interview, echoing Democratic talking points. Mullen isn't the only Democratic recruit preparing an unabashedly populist campaign. Party officials are optimistic about winning a rural, northeastern Arkansas district that Republicans hadn't carried since Reconstruction--until 2010, when now-Rep. Rick Crawford won the open seat. The district is one of the poorest in the country, and it has one of the lowest concentrations of college-educated whites in the country.