The warfare dimension taps into the strategies that go beyond defeating your opponents to humiliating them, go beyond questioning your opponents’ judgment to questioning their motives, and go beyond fighting the good legislative fight to destroying the institution and the legislative process. Partisan warfare serves electoral goals, not legislative goals.
When Democrats and Republicans can't reach consensus on the proper role of government in healthcare, that's partisan polarization. But when Rep. Paul Broun (R-GA) says that "Obamacare is going to destroy everything we know as a nation," that's partisan warfare.
As it turns out, partisan warfare, like polarization, is highly asymmetric. Animosity and ill will are significantly more concentrated at the conservative end of the ideological spectrum. Here are some charts from Pew breaking that down.
Conservatives dislike Democrats more than liberals dislike Republicans
"Today, the majority of ideologically-oriented Americans hold deeply negative views of the other side," the Pew authors write. "This is particularly true on the right, as 72% of consistent conservatives have a very unfavorable opinion of the Democratic Party. Consistent liberals do not feel as negatively toward the GOP."
Liberal animosity toward Republicans has actually ticked down slightly between 2011 and 2014, while conservative antipathy toward Democrats shot up sharply over the same period. Conservatives are even angrier at their own party - 6 percent of consistent conservatives have deeply unfavorable opinions about the Republican party, while 3 percent of consistent liberals feel the same about Democrats.
Conservatives are more likely to say that the opposition's policies are a threat to America
It what may be the most unsettling of the Pew survey's findings, large numbers of Americans say that people who don't share their political views are a threat to America. But as expected, the rate of distrust is higher among Republicans -- 36 percent of Republicans say the Democratic party is a threat to the nation's well-being. Only 27 percent of Democrats say the same.
Among the most partisan Republicans and Democrats, the gap is even larger: fully two-thirds of consistently conservative Republicans say that Democratic policies will harm the U.S. Only - "only" - half of consistently liberal Democrats say the same about Republican policies.
The Pew authors note that Obama Derangement Syndrome is one of the factors driving Republicans' intense distrust of Democratic policies. "At least in part, the strongly negative views Republicans have of the Democratic Party reflect their deep-seated dislike of Barack Obama," they write.
Conservatives surround themselves with people who share their views
Two-thirds of consistently conservative Americans say that most of their friends share their political views. Less than a third say many of their friends do not share their views. Even among mostly conservative Americans, there's a strong preference for politically like-minded friends.
Conversely, only a quarter of mostly liberal Americans say their friends share their political views, and more than 40 percent say that many of their friends do not have the same views. The most liberal Americans do show a preference for like-minded friends, but at a much lower rate (49 percent) than their conservative counterparts (63 percent).
Simply put, conservatives are much more likely to interact only with people who share their views, which reinforces those views even further.
The conservative echo chamber encompasses media too
It's no surprise that conservatives watch Fox News while liberals tune into MSNBC. But the Pew study shows that conservatives are much more unified in their preference for Fox - 74 percent of consistent conservatives have a favorable opinion of Fox, compared to only 45 percent of consistent liberals with a favorable view of MSNBC.
This is consistent with a recent study from the Public Religion Research Institute showing that Republicans' devotion to Fox is nearly absolute, while there is no similarly dominant news source among Democrats.
Compromise is not a conservative value
This may be the most telling chart in the Pew report. You'd expect partisans on either end of the ideological spectrum to be less fond of compromise than those in the middle. But as it turns out, compromise is basically a liberal value - 82 percent of consistent liberals prefer politicians who make compromises. Less than a third of consistent conservatives say the same.
It's important to note that when it comes to the actual practice of compromise, both liberals and conservatives have a hard time grasping what the word actually means. But liberals are much more into the notion of compromise as a political ideal. Conservatives, on the other hands, have a stated preference for candidates who "stick to their positions."
A party that is ideologically predisposed against compromise is going to have a very hard time governing, particularly within a divided government. You can see this reflected in the Tea Party's repeated enthusiasm for shutting the entire government down instead of passing pieces of legislation they disagree with.
A few weeks ago, Tom Mann wrote the following in The Atlantic:
Republicans have become a radical insurgency—ideologically extreme, contemptuous of the inherited policy regime, scornful of compromise, unpersuaded by conventional understanding of facts, evidence, and science; and dismissive of the legitimacy of their political opposition. The evidence of this asymmetry is overwhelming.
With the release of today's Pew study, that overwhelming evidence becomes even stronger.