Republicans consistently win voters making $50,000 or more, approximately the U.S. median income. The margin doesn't vary too much: In 2012, Mitt Romney got 53 percent of this group's vote; in 2010, Republican House candidates got 55 percent. And Democrats consistently win voters making less than the median—but the margin varies widely. In fact, whether Democrats win these voters by a 10-point or a 20-point margin tells you who won every national election for the past decade.
In 2004, Democrats won the working-class vote by 11 points; George W. Bush was reelected. In 2006, Democrats won the working-class vote by 22 points and took the House and Senate. In 2008, Democrats won by 22 points again, and President Obama was elected. In 2010, the margin narrowed to 11 points, and Republicans took the House back. In 2012, Obama was reelected—on the strength of another 22-point margin among voters making under $50,000.
So what does 2014 portend under this theory? Not good news.
The Pew report didn't include a breakdown based on the $50,000 threshold, so I asked Pew to crunch the numbers for me. The result: 51 percent of voters making less than $50,000 plan to vote for Democrats, while 40 percent plan to vote Republican. (The rest are undecided, and the GOP wins the more-than-$50,000 vote 49-44.) That's exactly the same 11-point margin that has meant Democratic doom in every election since 2004.
If we stay home again like in 2004 and 2010, the Republicans will win. If we vote like we did in 2006, 2008, and 2012, we'll win.
Really is that simple.