Kentucky is a pretty conservative place. President Obama lost the state to GOP nominee Mitt Romney by 22 points in 2012. All the same, it was a big win for the GOP on Tuesday when a Republican emerged victorious in the state's gubernatorial contest . Voters chose Matt Bevin, a wealthy businessman, over Jack Conway, the Democratic attorney general.

Many observers expected Conway to win, in part because Gov. Steve Beshear, whose term is expiring, is a popular Democrat. Beshear's appeal in Kentucky is exactly the kind of quirk in the political system that substantiated the old adage, "All politics is local." In other words, the unpopularity of a national figure such as Obama in Kentucky isn't as important as the regional, historical and individual factors that allowed a Democratic governor to succeed there.

[Read more: All politics are local? Think again.]

Those local differences, however, are becoming less consequential, according to some political scientists. These days, voters are casting ballots not for individual candidates whom they like, but rather against the political parties they dislike, and the national leaders of those parties. And in Kentucky, Obama and the Democratic Party are widely disliked.

That's why Democrats in Kentucky described the insurance exchange that Beshear established under Obama's health-care reform as unconnected to Washington or the president. Voters liked the exchange, called KYnect, even if they opposed the law known as Obamacare.

"I'd tell em we've got Beshearcare, and they'd be fine with that," Greg Stumbo, the Democratic speaker of Kentucky's House of Representatives, told The Washington Post's David Weigel.

[Read more: GOP win in Kentucky sets up unprecedented Affordable Care Act fight]

In Tuesday's election, though, voters' opposition to Obama had more to do with the outcome than their fondness for Beshear.

When polls showed Conway in the lead before the election, Republicans worried that Bevin was finished, Sheryl Gay Stolberg and Alan Blinder write in The New York Times. The polls didn't reflect how "reviled" Obama and the Democrats are in Kentucky, a local Republican Party leader told the reporters.

Political scientists Alan Abramowitz and Steven Webster of Emory University believe that shifts of this kind, from local to national political allegiances, are becoming more common.

Many researchers now think that anger at and fear of the opposing party, rather than enthusiasm for one's own party, are what motivates voters these days. As the chart below shows, while Democrats' views of the Democratic Party haven't changed, they see the Republican Party more negatively, and vice versa.


And Abramowitz and Webster argue that those negative emotions come from how the major political parties and the national figures who represent them are portrayed in the media, rather than voters' personal appraisals of particular politicians in their jurisdictions. In other words, loathing leads voters to paint candidates with a broader brush.

[Read more: These political scientists are discovering even more reasons U.S. politics are a disaster]

The South was a stronghold of Democratic politics for more than a century after Reconstruction. Some conservative Southerners began to vote Republican after President Johnson and his Democratic allies in Congress passed civil-rights legislation. Only in the past decade, though, have Democrats lost control of the region, in part because an older generation of conservative Democrats is being replaced by a younger one that votes Republican.

Such trends probably make it easier for voters in one party to despise the other. For a conservative voter in Kentucky who knows fewer and fewer conservative Democrats, it becomes more and more natural to assume that all Democratic candidates are cut from the same cloth.