In March, it was Kerry Emanuel's turn to do what so many of his colleagues have done before: defend their knowledge and expertise against congressional Republicans.

Emanuel is a meteorologist at the Massachusetts Institute of Technology, an expert not only on climate change but hurricanes. In the 1990s, he coined the term "hypercane" to describe a theoretical storm that, according to his equations, could have occurred in the wake of the asteroid impact that killed off the dinosaurs. But as the sole Democrat-invited witness before the House Committee on Science--the GOP majority had five, one a marketing professor who testified that "global-warming alarm is an anti-scientific political movement"--Emanuel's task was more like climate science 101. He merely had to stand up for what MIT teaches its students.

As Emanuel explained in his written testimony, today's MIT atmospheric-sciences students can do "hand calculations or use simple models" to show why global warming is a serious concern. Such calculations show that the planet will warm somewhere between 2.7 and 8.1 degrees Fahrenheit if we allow carbon-dioxide concentrations in the atmosphere to double. It's a result, Emanuel observed, that scientists have understood at least since 1979, when the U.S. National Academy of Sciences released the first in what are now shelves of studies of the subject. You don't get an atmospheric-sciences degree at MIT--with a climate focus, anyway--if you can't show on the back of an envelope what much of Congress now calls into question.

If Emanuel's testimony was at times cutting, it was also impassioned. Addressing the alleged "Climategate" scandal--which he'd served on a British Royal Society committee to investigate--Emanuel noted that "there is no evidence for an intent to deceive" on the part of climate researchers. He continued, his voice rising: "Efforts by some to leverage this into a sweeping condemnation of a whole scholarly endeavor should be seen for what they are."

All of which is what you'd expect to hear from a frustrated climate scientist these days--except, Emanuel is a proud, lifelong Republican. Or at least, he was until recently, when he voted for Barack Obama, the first time he's ever backed a Democrat. In 2008, Emanuel says, he was a "single issue" voter concerned about science and climate change. "I don't like it when ideology trumps reason, and I see that the Republicans are guilty of that in spades at the moment," he says.

"I've been toying with the idea of officially switching to independent status," he adds.

Kerry Emanuel's political journey isn't unique. Rather, it reflects a broader shift in the relationship between the U.S. political parties and America's scientific and technical experts, over the past several decades.

Increasingly, the parties are divided over expertise--with much more of it residing among liberals and Democrats, and with liberals and Democrats much more aligned with the views of scientists and scholars. More fundamentally, the parties are increasingly divided over reality itself: over what is actually true, not only about hard science but also social science and simple policy facts such as the contents of the health-care bill.

There's no doubt these two divides are connected, but the relationship between them isn't necessarily straightforward. It's not as if all the brains are on one side, and there's a total lack of them on the other. So before glorying in the fact that we have more facts, liberals might consider first blowing into an intellectual breathalyzer, to be sure we're not too intoxicated by our own seeming brilliance. After all, one thing our expertise does not appear to be doing is bringing the country back from the brink of a fully postmodern and fact-free discourse. In fact, it may even be contributing to the problem.

The expertise gap itself is becoming dramatic. In one of the most comprehensive surveys of American professors, sociologists Neil Gross of the University of British Columbia and Solon Simmons of George Mason found that 51 percent described themselves as Democrats, and 35.3 percent described themselves as independents--with the bulk of those independents distinctly Democrat-leaning, rather than straddling the center. Just 13.7 percent were Republicans. Academia has long been a liberal bastion, but it hasn't always been this lopsided. According to Gross, professors have been drifting to the left since the late 1960s, gradually carrying us into today's very unbalanced expertise environment.

Gross and Simmons' findings parallel the results of surveys on two overlapping groups: scientists and those with graduate degrees (whether or not they stay in academe). A 2009 survey of American Association for the Advancement of Science members found they were overwhelmingly more Democratic, and more likely to describe themselves as liberal, than the general public. Fifty-five percent were Democrats, 32 percent were independents, and just 6 percent were Republicans. Then there are all the folks with letters after their names. Ruy Teixeira of the Center for American Progress has shown that Americans with a post-graduate level of education have been trending more and more strongly Democratic in the past three presidential cycles. They supported Al Gore by a margin of 52 percent to 44 percent in 2000, John Kerry by 55 percent to 44 percent in 2004, and Barack Obama by 58 percent to 40 percent in 2008.

The Democratic Party has thus become the chosen party of what you might call "empirical professionals" and Americans with advanced degrees. According to research Gross conducted with Ethan Fosse of Harvard University and Jeremy Freese of Northwestern University, nearly 15 percent of U.S. liberals now hold one, more than double the percentage that did in the 1970s. The percentage of moderates and conservatives with advanced degrees has also increased but lags far behind the saturation levels of expertise among liberals. Indeed, conservatives are about where liberals were back in the 1970s. As a result, the researchers write, "more so than ever before the highly educated comprise a key constituency for American liberalism and the Democratic Party, one that may have surpassed a crucial threshold level in size."

How did this happen? Part of the answer is surely obvious: In recent decades, the Republican Party's rightward shift alienated many academics, scientists, and intellectuals. Indeed, that's how Kerry Emanuel accounts for his own political transformation. In the early 1970s, as an undergraduate at MIT, he remembers feeling surrounded by the "liberal excesses" then prevalent in the "People's Republic" of Cambridge, Massachusetts. "I remember hearing fellow students defending Pol Pot and Mao Zedong and Stalin, and I was so horrified," he says. But now Emanuel sees the situation as reversed: The extremes are on the Tea Party right, the Democrats are centrists and pragmatists, and Emanuel--really always a moderate--finds not so much that he has moved but that his party has. "I'm turned off by those people for exactly the same reasons I was turned off by the ideologues of the 1970s," he says.

But another critical part of the explanation is that at around the same time that Emanuel was perceiving those liberal excesses, so were many others on the right--and they decided to do something about it. Since the 1970s, Republicans and conservatives have not only been slamming universities as bastions of liberal bias but have forged a fleet of think tanks, such as the Heritage Foundation and the Cato Institute, whose task is to hit back against liberal expertise.

The growth of conservative think tanks parallels the leftward migration of expertise in general: Call it a countertrend. Indeed, writes Columbia historian Mark Lilla, many conservatives in the 1970s and 1980s began to operate as "counter-intellectuals," consciously dedicated to fighting back against the "intellectuals" as a class. In some cases, they became "counter-intellectuals without ever having been intellectuals--a unique American phenomenon."

Another historian who has studied the growth of think tanks, Jason Stahl, spent months in the Library of Congress with the papers of William J. Baroody Sr., the longtime head of the conservative American Enterprise Institute. Based on this research, Stahl finds a very similar result. Baroody presided over the dramatically successful growth of his institute, from a staff of 18 and an annual budget of just over $1 million in 1970 to a staff of 150 and a budget of $10 million by the early 1980s. He did so by inspiring conservative and corporate funders to "break [the] monopoly" on ideas held by the left and to ensure that "the views of other competent intellectuals are given the opportunity to contend effectively in the mainstream of our country's intellectual activity."

So it is not as though conservatives lack intelligent and talented experts of their own. Democrats may have considerably more of them in their ranks than Republicans, but Republicans have more total experts than they used to, as well--the whole society does. And despite Stephen Colbert's remark that "reality has a well-known liberal bias," Republicans are not giving in. They're fighting that "biased" reality constantly, in as many disciplines as they can. For every Ph.D., there's an equal and opposite Ph.D.--or so it can often be made to appear.

Granted, in many of these battles, conservative "experts" don't really end up faring very well. Sniping at climate science from a few D.C. institutes and citing a few sympathetic scientists may turn friendly ears in Congress. But it does nothing to seriously undermine the conclusions and legitimacy of virtually every scientific society that can claim expertise in the subject, or of the national academies of nations around the world.

Another case where conservative expertise flounders is Christian-right "science." Conservative Christians always have their own experts on hand to make convenient arguments on matters of science and social policy---usually experts who are also pro-life, devout Christians. There are conservative Christian Ph.D.s who attack evolution (chiefly housed at Seattle's Discovery Institute), who downplay the effectiveness of contraception, who argue that abortion harms women physically and mentally and causes fetuses pain. These critiques, however, are all far outside of the scientific mainstream (at best).

Or take this example of recent relevance--attempts to use social "science" to undermine same-sex parenting. As more states and localities allow same-sex marriage, more of these couples will also become partners in raising children, and indeed, many are already doing so outside of marriage. Accordingly, religious conservative experts have sought to show--sometimes in court--that social and psychological damage is inflicted on children raised in same-sex households or that they're indoctrinated into the gay lifestyle.

But the strategy isn't going very well, because, as the American Psychological Association explains, the relevant research shows that the "development, adjustment, and well-being of children with lesbian and gay parents do not differ markedly from that of children with heterosexual parents." How do you counter an organization with so much expertise and credibility? Christian conservatives and their allied experts strive to find a "scientific" counterargument, but it's pretty thin gruel.

One go-to person for the Christian right has been the psychologist and Baptist minister George Rekers, who has testified in several court cases involving gay adoptions and foster care. Rekers has written that "to search for truth about homosexuality in psychology and psychiatry, while ignoring God, will result in futile and foolish speculations." Not surprisingly, he contests the research showing that that the kids are all right in homosexual families and argues that gay parents are more likely to have tumultuous relationships, substance-abuse problems, and various psychological conditions. In Arkansas and in Florida, however, judges have strongly criticized his testimony. "Dr. Rekers' beliefs are motivated by his strong ideological and theological convictions that are not consistent with the science," wrote District Court Judge Cindy Lederman in a 2008 Florida gay adoption case. "It was apparent from both Dr. Rekers' testimony and attitude on the stand that he was there primarily to promote his own personal ideology," wrote another judge, Arkansas' Timothy Davis Fox, in a 2004 case involving gay foster care.

In other words, conservative counter -- expertise forays are often easily unmasked. They haven't fared well in court (whether in cases involving evolution or same-sex parenting) or gained purchase within the scientific community.

For an amusing example of this expertise imbalance, consider Project Steve. This is a ploy by the pro-evolution National Center for Science Education to undermine conservative sign-on letters boasting large numbers of "experts" who question the theory of evolution. Project Steve goes one better--it finds scientists named Steve who support evolution. To date, over a thousand Steves have signed on--and, as NCSE boasts, Steves constitute only about 1 percent of scientists.

So, yeah--we liberals have lots of high-caliber experts. And a lot of good it is doing us.

The problem is that with expertise, even if you're outgunned, you can fight a guerilla war very successfully. The reasons are rooted not only in the way the media now operate but also in human psychology.

There's been much discussion of late about how we somehow landed in a "post-fact" world--the existence of which former presidential press secretary Robert Gibbs recently acknowledged. After President Obama decided to release his long-form birth certificate, Gibbs remarked, "There are no more arbiters of truth. So whatever you can prove factually, somebody else can find something else and point to it with enough ferocity to get people to believe it. We've crossed some Rubicon into the unknown."

Many blame this development on the Internet echo -- chamber effect--online, people can clump together in like-minded groups to affirm even the most fevered ideas. And certainly that is part of the problem. But the dynamics of expertise and counter-expertise are also fundamental to the explanation, perhaps even more so. The Internet didn't bifurcate us over reality--we were already cleaving long before it existed (though surely the Web sped up the process).

Once you had liberal experts squaring off against conservative experts and wielding liberal and conservative "science," you would expect a postmodern result--for multiple reasons. One is based on psychology and neuroscience. The theory of "motivated reasoning" explains how our brains interweave concepts, ideas, and associations that are central to our identities with strong emotions--so that before we're even consciously "reasoning," we're already building a case in defense of our personal, political, or ideological preconceptions. This most emphatically applies to experts--among the more intelligent, knowledgeable, and sophisticated among us, there are reasons to think the process is even more advanced, not less. Precisely because of their training and ability--their power at selectively constructing arguments--the politically or intellectually sophisticated are better able to justify themselves and also to convince themselves that they're right.

You see this in the data. On global warming, Democrats and Republicans who think they know less about the issue are closer to each other in their views about whether it is really happening. By contrast, Democrats and Republicans who think they know a lot about the issue are completely polarized, with Republicans quite confident the science is wrong. Precisely the same occurs on nonscientific but factually contested issues, such as the myth that the health-care reform bill empowered government "death panels." According to research by political scientist Brendan Nyhan of the University of Michigan, Republicans who thought they knew more about the Obama health-care plan were "paradoxically more likely to endorse the misperception than those who did not." Again, well-informed Democrats were the opposite--quite certain there were no "death panels" in the bill.

Thus, we would expect to see liberal and conservative experts constantly arguing with each other, each sounding reasonable and articulate--and each becoming more convinced they're right the more they argue and the more they research the issues. As this process plays out, it has numerous pernicious effects. One is that many onlookers to these debates are left confused and frustrated about where reality lies on any contested issue. Another is that partisans on either side wind up with lots of handy arguments to carry into their own belief-affirming and confidence-bolstering intellectual battles.

And when the media take up the debate, it's still worse--the more they equivocate and "balance out" the two perspectives, the more many citizens who consume such coverage feel unable to determine what the truth is about politics and are left unmoored in a postmodern world.

In a recent study, Ohio State University communications professor Raymond J. Pingree asked subjects to read fake news stories in which two political camps were depicted as arguing over the economic and other implications of a proposed health-care law. Some of the articles took a stand on the objective truth of the matters in question; others did not. Pingree's subjects were then asked a variety of questions, such as how much they agreed that "if I wanted to, I could figure out the facts behind most political disputes." Those who read the journalistically passive articles--the ones that failed to adjudicate between the "facts"--felt less sure that they could do so themselves. Those who read the more journalistically active articles were more confident in their own powers of discernment.

Media equivocation notwithstanding, there are indeed facts--and the evidence suggests that while they certainly are not always right, Democrats these days are more likely, overall, to believe the truth on contested issues. Take health care. Earlier this year, the Kaiser Family Foundation released an examination of mistaken beliefs about the new law, and misperceptions were certainly rampant. Fifty-nine percent wrongly thought the law creates a government-run health-care plan; 40 percent believed it creates "death panels" (another 15 percent were "unsure"); and 45 percent thought the law cuts benefits to those on Medicare. These misperceptions were not equally distributed in the population--Republicans were more likely to believe the last two falsehoods in particular. Indeed, just 18 percent of Republicans came up with the right answer for at least seven of the 10 factual questions the survey posed, compared to 32 percent of Democrats.

That's not the only such study. Shortly after the 2010 election, a group of pollsters out of the University of Maryland asked Americans how much misinformation they felt they had encountered during the campaign. Sure enough, members of both parties agreed the air had been thick with false claims--more of them, they said, than they could remember having encountered before. But when the pollsters then asked about a variety of contested factual issues in the campaign, Republicans appeared considerably more misinformed than Democrats. Out of 11 factual topics pertinent to the election, Republicans were 10 percentage points or more wrong about seven of them, including whether President Obama was born in the U.S., whether global warming is happening, whether the health-care law would increase the deficit (it would not), and whether the stimulus bill created or saved millions of jobs (it did). (One issue--whether the General Motors and Chrysler bailout happened under both Bush and Obama--it did--was nearly a wash, with Republicans only slightly more wrong than Democrats.)

Both of these studies also found--as several studies have found before--that watching Fox News correlated with being more misinformed about the issues. Conservative counter-expertise and the conservative echo chamber (broadcast, online, or otherwise) are deepening the problem.

None of this is to say, of course, that Democrats are never wrong--or never more likely to be wrong. For instance, a 2006 survey found they were more likely than Republicans to endorse the wild "truther" conspiracy theory about the Bush government being complicit in the September 11 attacks. Yale law professor Dan Kahan, meanwhile, has shown that citizens with "egalitarian" and "communitarian" values (liberal Democrats, for example) are more likely to question the safety of storing nuclear waste deep underground, a view that puts them at odds with a 1990 National Academy of Sciences report on the subject.

We don't universally have truth on our side, then, and we're certainly capable of engaging in "motivated reasoning." Yet we really do have vastly more experts, and on the leading political issues of the day--climate, health care--we really do seem to be more factually correct. But what should we do about it? It is not as if our facts and our expertise are solving any contested policy issues or resolving any disputes.

To gain some perspective on the problem, follow this thought experiment. Suppose there were a counterfactual world in which most experts were conservative, but there was a minority of liberal experts who fought back against them tirelessly--very sure of themselves and never the least disturbed (or, perhaps, aware) that they are usually wrong. But wait--just by posing the experiment, we quickly see why that world doesn't sound very believable. It's not that liberals can't be wrong: As we've seen, they can. But they would never be so sure of themselves. Aren't liberals famous (or infamous) for bending over almost backward to hear the other side?

We are now getting to the complicated question of why most academics today are liberal. Surely the rightward movement of the Republican Party has something to do with it, as do the repeated attacks on academia from the conservative movement over the decades. Ironically, though, one key premise of these attacks--the idea that institutions of higher education make one a liberal, through a kind of brainwashing process--is questionable. More and more evidence suggests that for most of us, our political identities are already largely determined well before we reach the point of choosing career paths, and then we select desirable life choices (a doctorate, for one) based in part on those identities. Neil Gross' research with Fosse and Fresse, for instance, suggests that the expertise gap is likely the result of a "self-selection process," fueled by the fact that for liberals, academic jobs hold prestige--but for conservatives, they're not considered attractive nowadays. That's partly because academia has been repeatedly smeared as a liberal bastion and perhaps also partly because of differing values: Ambitious and smart conservatives would rather work on Wall Street.

However, the researchers admit that their analysis can't rule out another explanation supported by growing evidence--the idea that conservatives and liberals are just different, in aggregate, when it comes to personality types and moral systems. If true, this would surely affect liberals' and conservatives' career choices, too, as well as how they argue about fact-based or expertise-based issues.

At least one highly influential expert on liberals and conservatives, the Berkeley cognitive linguist George Lakoff, views this as a central factor in our fights over science and expertise. In an interview for this article, Lakoff suggested that left-right divides over science have their roots in the cognitive structures and metaphors that, he argues, drive our political schisms in general. Conservatives don't dislike science or expertise inherently, Lakoff says--but for them, these are not the chief source of authority. Instead, conservatives have a moral system based on a "strict father" model of the family, which is then exported to various other realms of society--the market, the government. All are meant to be governed in a ruggedly individualistic, free-market way--where you either succeed or you don't, based on your own mettle. In this context, science and expertise can be very good for supporting some views--the science of drilling, the science of nuclear power--but they can also be an unruly guest at the party. Scientific evidence "has a possible effect over the market, foreign policy, religion, all kinds of things," Lakoff says. "So they can't have that."

Liberals, to Lakoff, are just different. Science, social science, and research in general support an Enlightenment ethic--finding the best facts so as to improve the world and society and thus advance liberals' own moral system, which is based on a caring and "nurturant" parent-run family. "So there is a reason in the moral system to like science in general," Lakoff says. Here also arises a chief liberal weakness, probably amplified by an academic training: constantly trying to use factual and reasoned arguments to make the world better and being amazed to find that even though these arguments are sound, well researched, and supported, they are disregarded or even actively attacked. Too often liberals--we--fail to see how our very credentials, and the habits of argument they impart, set the stage for the postmodern world just as soon as our unending factual dance with conservatives begins.

Lakoff's views emerge from his own specialty--cognitive linguistics--but they're broadly consistent with a growing body of research on the moral, personality-based, and psychological differences between liberals and conservatives. In aggregate, liberals seem more characterized by cognitive "flexibility," whereas conservatives are more inclined to think in fixed categories, seeking yes or no answers. When it comes to personality, liberals tend to be more open to new and not entirely predictable experiences (travel, the arts), as well as abstract ideas, while psychologists describe the conservative personality as characterized by conscientiousness (keeping things orderly, on schedule, neat). And then there are the moral systems--Lakoff's strict-father family versus a nurturant parent or, in another schematic mentioned earlier, hierarchical and individualistic values versus communitarian and egalitarian ones.

Factoring in all (or even some) of these characteristics, we would expect to see more liberals who want to be scientists or researchers, who want to use science and expertise to serve social goals by advancing knowledge--and who revel in the details, complexity, and ambiguity of the research endeavor. Whereas conservatives would not be anti-science or anti-intellectual but would tend to use research and expertise to support other agendas. They would also tend to reject results that seem to counter these agendas--all the while being quite sure of themselves and happy to argue the point.

So do all of us, left and right, care about expertise? Sure, when it suits us. We also usually agree about where expertise lies--when it isn't contested. "You would certainly be horrified if you found out the guy who was flying your airplane didn't have a pilot's license," Kerry Emanuel says.

Politically, though, we use expertise in service of different agendas--and reason for different reasons. And we don't all necessarily share the Enlightenment ethic of using science and research to lift us all up into a more caring and progressive society. Indeed, liberals who do share this ethic often don't seem to understand what's happening when reasoned, evidence -- based arguments fail to have their desired effect--and are countered by flimsy objections or unjust attacks.

We've got a lot of science, a lot of experts--and a lot to learn.