Political denunciation is an art form too rarely analyzed.

To be effective, a rhetorical attack must be sharp-edged and clever enough to wound, but also accurate enough to reveal something true about the object of scorn. Otherwise, the epithet is just empty name-calling that won't have any lasting impact.

The classics of the genre fit this description precisely. Think of liberals denouncing conservatives as "the stupid party." Are all conservatives stupid? Of course not. But the right does embrace a populist rhetoric fueled by suspicion of "experts," and it tends to rally around politicians who champion (and channel) the folksy wisdom of "ordinary Americans." That's why the label hurts — because it reframes the right's cultural populism in a plausible and unappealing way, as if it positively embraces stupidity as an ideal.

Something similar is going on when conservatives describe liberals as "socialists." Do most liberals believe in the government takeover of the economy and the imposition of confiscatory tax rates? Of course not. But unlike conservatives, they do believe the government has an important role to play in redistributing wealth and ameliorating social injustices. That makes them vulnerable to the charge that their pro-government impulses are limitless — which could, in theory, lead liberals to advocate outright socialism.

Then there are the denunciations that miss their targets completely. At the top of my list of failed political put downs, I'd place the charge of "moral relativism."

On the right, the habit of unmasking the supposed relativism of liberals goes back at least to Allan Bloom's surprise 1987 bestseller The Closing of the American Mind, which claimed that liberal education was turning American college students into moral relativists. Today, one hears similar charges from the right-wing media complex almost daily: liberals refuse to uphold the ideology of American exceptionalism with sufficient vigor; they decline to defend limited government and free enterprise against their opponents in other regions of the world; they won't speak the harsh truth about radical Islam and its existential threat to the West — and all because they've abandoned the idea of absolute moral Truth.

But as libertarian blogger Bryan Caplan notes in a recent post, conservatives are equally vulnerable to the charge of relativism. The right regularly expresses indifference to world-historical evils committed by the West and the United States: the Crusades; the slavery and racism that's intertwined with so much of American history and taints the lives of so many American heroes; the ethnic cleansing of Native American populations; and so on.

So are both sides of the spectrum awash in moral relativism?

Not according to social psychologist Jonathan Haidt. The Moral Foundations Theory he develops in his important 2012 book The Righteous Mind points, instead, toward the opposite conclusion — namely, that most liberals and conservatives are deeply attached to morality, albeit to moralities of somewhat different types.

Haidt lays out six distinct moral foundations.

1. Care (the desire to help those in need and avoid inflicting harm)
2. Liberty (the drive to seek liberation from constraints and to fight oppression)
3. Fairness (the impulse to impose rules that apply equally to all and avoid cheating)
4. Loyalty (the instinct to affirm the good of the group and punish those who betray it)
5. Authority (the urge to uphold hierarchical relationships and avoid subverting them)
6. Sanctity (the admiration of purity and disgust at degradation)

According to Haidt's experimental research, social conservatives affirm the validity of all six foundations. Libertarians focus very heavily on liberty and a modest amount on fairness, while showing something close to indifference on the rest. Liberals, for their part, emphasize (in descending order of intensity) care, liberty, and fairness, and express little concern about the others.

Viewed through the lens of these differing moral foundations, we can see that positions frequently described as expressions of moral relativism actually flow from deeply moral assumptions and commitments. Liberals, for example, tend to be highly skeptical about American exceptionalism not because they deny moral truth, but because they are suspicious of group loyalty and highly concerned about making fair (impartial) judgments. Their intense concern with care, meanwhile, makes them eager to expose the times in American history when ordinary citizens as well as national heroes have inflicted harm.

Liberals and libertarians like Caplan, on the other hand, can point to the comparative indifference to these same acts of harm among conservatives as evidence that they're relativists. But in fact, conservatives are merely somewhat less fixated on harm and much more concerned with group loyalty. The conservative moral matrix might rub liberals and libertarians the wrong way, but it's not an outgrowth of relativism. Rather, it's a sign of a distinctive (and different) form of moralism.

But Haidt's own treatment of liberalism — which posits indifference toward loyalty, authority, and sanctity — may actually understate the breadth of liberal moral commitments. Liberals may be skeptical about national loyalty, but they regularly pledge allegiance to fellow liberals of any culture or country. They may be disinclined to defer to the authority of political and religious leaders, but they readily recognize and affirm the authority of scientists, artists, writers, professors, and other intellectuals. They may be less likely to revere religious institutions and traditions, but they do sometimes treat their own heroes and leaders with a reverence bordering on sanctity, just as liberal environmentalists sometimes treat the planet as sacred and judge despoiling it an act of desecration.

All of which goes to show that pretty much no one in our politics and culture is a moral relativist. Our conflicts involve clashes among distinct moral outlooks — or rather among distinct mixtures of highly complex moral outlooks.

We need to find another form of political denunciation.