Race relations are arguably worse now than they've been at any point during my lifetime. (This is not as controversial of an opinion as it might sound — even Jimmy Carter agrees.)

The problem is sweeping, and it afflicts partisans of all stripes. This weekend, the Washington Post's Dan Balz observed, "The discontent is real, whether economic, racial, or cultural. It knows no particular ideological boundaries. It currently disrupts both the Republican and Democratic parties." Meanwhile, The New York Times' Jonathan Martin and Maggie Haberman note that, "On the left, young black activists, furious about discrimination and inequities in criminal justice, say the usual rhetorical nods toward equality, incremental increases in funding for housing or education, and vague promises of change from mainstream political leaders are inadequate," and "on the right, by contrast, blue-collar conservatives have responded to Mr. Trump, who has given voice to their fears about what they see as America’s identity crisis."

Yes, as is so often true these days, it comes back to Donald Trump. Consider his surge in popularity — not in spite of his comments about Mexicans being rapists (some, he assumes, are good people), but arguably because of them. And on the left, how about that Netroots Nation meeting where Bernie Sanders — a civil rights activist — was shouted down, and where former Maryland Gov. Martin O'Malley was forced to apologize for daring to suggest that "all lives matter."

Of course, America's race relations issues have myriad causes, many of them centuries in the making. But today, an increasingly vocal contingent of people on both sides are very angry — and essentially preaching a message of exclusivity and separatism.

Let's begin with the white supremacists who have coined an ugly new term called "cuckservative" to skewer conservatives who are more interested in ideas and inclusion than tribalism. I've been on the forefront of pushing back against this term's usage — as has Erick Erickson and other mainstream conservatives. (The term, as you might have guessed, has both racial and sexual implications.)

This "cuckservative" explainer comes from a white nationalist website:

They are like a man who tries to appeal to a woman through acts of submission; they inspire not desire but disgust. Each new conservative surrender inspires only further contempt in the hearts of leftists, which of course encourages conservatives to capitulate even more eagerly the next time. And since the conservative base remains overwhelmingly white — this proves it is "racist" — there will always be a next time. There's also the variety of cuckold who gets a thrill from watching another man mount his wife. Such a creature possesses the illusion of control. He can tell himself that he is directing this obscenity and thus remain, in some way, the dominant figure.

The "cuckservative" slur has gained prominence in recent weeks, as it has largely been deployed against conservatives (like yours truly) who would dare criticize Donald Trump for his rampant racism. Make no mistake: There is a real strain of racism on the far right, and Trump's surge seems to have emboldened them to scurry out of the shadows to skewer the vast majority of American conservatives who actually have compassion and humanity.

Meanwhile, the left is hardly blameless in its approach. (Take the strategy of "Black Lives Matter" protesters harassing white children at restaurants, for instance.) There are unsavory tactics and images being employed on both sides to tear us apart. The primary difference — and you may have already viscerally felt it after reading these examples in succession — is that many of the people fueling the problem on the left are operating under a more respectable veneer. They are often embraced by elite intellectuals.

Of course, there are plenty of mainstream conservatives pushing back against the far right, and likewise, there are African-Americans questioning the conventional wisdom of the "Black Lives Matter" movement. (I urge you to watch this conversation between Brown University Professor Glenn Loury and John McWhorter.)

But there is a difference: While Loury seems to be an exception, numerous mainstream conservative opinion leaders have been outspokenly critical of Trump, and have quickly sought to tamp down the "cuckservative" slur. Maybe you don't agree that the angry populism on the left is equivalent to what we're seeing on the right. But it's still there. What's missing is an equal effort on the left to call for comity. When Martin O'Malley is forced to apologize for declaring that all lives matter, you know things are bad.

The sad thing is that there are race-related issues, like criminal justice reform, that good people on both sides of the aisle should be working toward. But passing meaningful reform will require building a coalition. That means addition, not subtraction. That requires inclusion, not exclusion — which is essentially the opposite of what happens when you rally around a presidential candidate spouting racism, or burn another for daring to suggest that all lives matter.

We used to believe in a pluralistic society. This was a foundational American value embraced by mainstream conservatives and liberals, Republicans and Democrats. Today, that whole notion is being challenged by some increasingly loud voices on the left and the right. It's time for good men and women to stand up to this. We might not agree on the details of politics, but we ought to at least be able to agree that all lives matter.