Most senators up for reelection know their campaigns bear little resemblance to the races they ran six years ago, but even these incumbents might not understand just how dramatically voter identity has changed since 2008.
Their states, in short, have a whole lot more independents.
That's according to a new study from Third Way, a center-left think that examined up-to-date voter-registration figures in 10 states with competitive Senate or gubernatorial contests. The analysis, shared first with National Journal, depicts an electorate that over the past six years has become increasingly eager to embrace a nonpartisan label.
The top-line numbers are striking: 1.3 million voters have registered as independents since 2008, a 17-percent increase. In the same 10 states, Democratic registration has shrunk by 658,000, or 5 percent, while GOP registration has grown by roughly 360,000, or 3 percent.
The study posits that the surge in independent registration is indicative of an electorate dissatisfied with just about everything in politics and, consequently, distancing itself from all of it.
"They're unhappy with Congress, they're unhappy with the president, and as a result, they're checking 'none of the above,' " Michelle Diggles, the study's author and a senior political analyst at Third Way, told National Journal. "It's like a pox on both houses."
Party affiliation doesn't determine which candidate a voter will ultimately choose—many Southern Democrats long ago stopped voting for their party's presidential nominee. And professional pollsters view demographic shifts, such as increases in racial minorities or unmarried women, as more important metrics.
But studying the changes is useful in assessing how much a state has changed politically since 2008, a political high point for Democrats. And it underscores the importance for both party's candidates of appealing to an ever-larger bloc of voters who don't regard themselves as partisans.
North Carolina, for instance, features one of the nation's most competitive Senate races, between Democratic Sen. Kay Hagan and GOP challenger Thom Tillis. Since Hagan's 2008 victory, independent registration has spiked almost 30 percent, or by nearly 400,000 voters. The Tar Heel State now has almost as many independents as Republicans: 1.79 million to 2 million, respectively.
Colorado is another battleground, with Republican Rep. Cory Gardner trying to unseat Democratic Sen. Mark Udall. And there, like in North Carolina, independent registration has spiked—by 40 percent, or nearly 300,000 voters. Colorado has long been one of the states with the highest number of independents: It now has more of them, roughly a million in total, than either Republicans or Democrats.
The study's results might elicit the most interest in Kansas, where a pair of GOP incumbents, Gov. Sam Brownback and Sen. Pat Roberts, are in tough fights to win reelection despite the state's Republican leanings. Third Way found that the biggest shift in Kansas since 2008 was a 13-percent decrease in registration for Democrats, who lost more than 60,000 voters. But it also reported an 11-percent bump among independents, good for 53,000 additional voters.
Independents generally lean right: President Obama won only 45 percent of them in the last election. As the study highlights, however, Democratic candidates perform better with independents in Kansas than elsewhere. Roberts, who won 60 percent of the total vote in an uncompetitive 2008 race, won just 50 percent of independents that year. In this year's more competitive race, with high-profile independent challenger Greg Orman, Roberts's share might be poised to shrink.
"There does seem to a shift toward independents, and they aren't overwhelmingly Republican there—at least not recently," said Diggles.
Despite a small decline, Democrats still hold an overall registration advantage in the states, with nearly 13 million voters identifying themselves with the party. More than 11 million voters are registered as Republicans, while 9 million are registered as independents.
The 10 states whose voter registrations were assessed as part of the study were Alaska, Colorado, Florida, Iowa, Kansas, Kentucky, Louisiana, Maine, New Hampshire, and North Carolina.