Understanding the independent voter is the white whale of politics. Strategists in both parties spend inordinate amounts of time trying to grasp why these fence-sitters feel the way they feel — and what message makes them vote Democratic or Republican on Election Day.

How can independent voters who supported Democratic House candidates by 18 points in 2006 turn around and back Republicans running for the House by 19 points just four years later? And what does that movement tell us about where independents might end up in the 2014 midterms and, eventually, the 2016 presidential election?

Those are the questions Micah Roberts of the Republican polling firm Public Opinion Strategies seeks to answer in a new memo that combines years of NBC-Wall Street Journal polling data on independents. (While Roberts works at a partisan firm, the NBC-WSJ survey is conducted by Democratic and GOP firms working together, and the data are widely regarded as among the best in the polling business.)

Here’s what Roberts did: He merged all of the monthly information on independents for 2010, 2012 and 2013, giving him a huge — and statistically rigorous — group of independents in each of those years.

What he found provides a bit of good news for a Republican Party that seems determined to rip itself apart.

On the question of congressional preference — Which political party would you prefer controlled Congress? — independent voters in 2013 lean more heavily toward the GOP than they did in 2010, when Republicans picked up 63 seats to retake control of the House. In 2010, 40 percent of independents said they wanted a GOP-controlled Congress, while 26 percent said they wanted a Democratic-led one. In an NBC-WSJ survey from July to September of this year, 43 percent of independents said they wanted GOP control, while 25 percent preferred a Democratic House majority. (NBC-WSJ began asking the congressional-preference question for this year in July, hence the lack of a year’s worth of data.) By contrast, in 2012, when Democrats picked up eight House seats, independents were split — 35 percent Democrats, 34 percent GOP — when it came to which party they wanted to control Congress.

(Worth noting: Roberts’s analysis is based on a single question — congressional preference — over time. Although it is considered a strong, broad gauge, it should not be taken as the end all, be all of data points.)

The reason for the GOP tilt of independents? Roberts thinks it has much to do with President Obama's faltering numbers among that group. In the third quarter of this year — July to September — 50 percent of independents surveyed by NBC-WSJ had a negative image of Obama, while 32 percent had a positive image. Six in 10 disapproved of the job he was doing overall; in particular, 63 percent disapproved of his handling of the economy. Throw in the fact that nearly three-quarters (72 percent) of independents surveyed in the third quarter of 2013 think the country is on the wrong track and it becomes clear why independents are aligning with Republicans.

Are these just Republicans who are disgusted with the state of the party and are temporarily identifying themselves as independents? (Remember that Mitt Romney actually won independents by five points over Obama in 2012 but still lost the election convincingly.) No, said Roberts, who analyzed the demographics among independents across 2010, 2012 and 2013 and found remarkable similarities in the group’s makeup. In 2010, a great year for Republicans, 58 percent of independents were men. Two years later, a good year for Democrats, 55 percent of independents were men. In 2013, 56 percent of them are men. The story is the same across age, ideology and geographic region. Those identifying as independents in 2010 and 2012 look a lot like people who call themselves independents today.

Viewed broadly, the data on independents culled by Roberts make one thing clear: Republicans are well positioned among electorally critical independent voters heading into the 2014 election if — and this is a major if — the party can keep the focus on Obama and off its internal rifts, which have been on full display over the past week. Independent voters want to vote for Republicans — if only the GOP could get out of its own way.