As the Supreme Court considers rendering unto itself the right to redefine marriage -- that is, to arrogate to itself something heretofore reserved to the laws of nature and nature’s God -- it’s a good time to have something that liberals always insist we have: a conversation. And given liberals’ constant calls for “tolerance” and “diversity,” they ought to be willing to sit back and join us in a civil, healthy dialogue.

To that end, I invite them to consider something so crucial and yet so neglected that I wrote a full book on it, released just in time for this national conversation on marriage. It’s titled, Takedown: From Communists to Progressives, How the Left Has Sabotaged Family and Marriage, and I sincerely wish liberals would lend it their professed toleration and open-mindedness.

Before I share my thesis, I should clarify my own stance.

I support the natural-traditional-biblical definition of marriage that has been Western civilization’s standard for multiple millennia. My position echoes my Roman Catholic faith. Basically, in a nutshell, my position is Pope Francis’ position (properly understood). Though Piers Morgan marvels at my position as “extraordinary,” it’s merely the one held by your grandparents, great grandparents, great-great grandparents… great-great-great-great-great-great-great grandparents and the ongoing long line of ancestors who preceded them. Even the ancient Greeks and Romans, long viewed as the models of perversity, never broached the unthinkable prospect of same-gender people marrying. That simply has never been marriage. What millions of Americans are rushing to do right now is completely unprecedented.

Today’s leftists should understand that they are the new One Percenters. They stand against the literal 99%-plus of humans who ever bestrode the planet, who never conceived of marriage as anything beyond man and woman.

As for those who disagree with me, and no longer support marriage as reserved to one man and one woman – a redefinition which will ultimately open the door to numerous new configurations -- I’d like to address you politely with a point I’m sure you haven’t considered. Do I expect to change your mind or those of Elena Kagan or Ruth Bader Ginsburg or the wider culture? No, I don’t. America has entered a protracted phase of post-Judeo-Christian thinking, where individualism and relativism reign supreme, fostered by a steady stream of incredibly naïve parents who marched their children in wide-eyed cadence through the educational system at giant costs both financial and moral. Nothing short of a major religious revival will save it. This culture and country will redefine marriage, either this month or in the months and years ahead.

That said, I would like to inform gay-marriage supporters of something they haven’t considered. Here it goes, a brief summary of what I detail over a couple hundred pages in Takedown:

Efforts to fundamentally transform family and marriage have been long at work, but never (until now) accepted and pushed by the mainstream. In the past, these efforts were spearheaded by the most dangerous leftists. For two centuries, leftist extremists made their arguments, from the 1800s to the 1960s, beginning with the Communist Manifesto, where Marx and Engels wrote of the “abolition of the family!” Efforts to revolutionize family and marriage continued from socialist utopians like Robert Owen, Charles Fourier, and Albert Brisbane, to cultural Marxists in the Frankfurt School such as Herbert Marcuse and Freudian-Marxist Wilhelm Reich, to 20th-century leftists and progressives ranging from the Bolsheviks -- Lenin, Trotsky, Alexandra Kollontai -- to Margaret Sanger, Betty Friedan, Kate Millett, and ‘60s radicals like Bill Ayers, Bernardine Dohrn, and Mark Rudd. When Tom Hayden and Robert Scheer ran a “Red Family” colony in near Berkeley in the 1960s, they were merely following the footsteps of socialist-utopian colonies in the 1800s in places like Oneida, New York and New Harmony, Indiana.

Were these “ideological colonists” (to borrow an apt description by Pope Francis) supporting gay marriage? Of course, not. No group of radicals, no matter how unhinged, ever contemplated that. The mere fleeting contemplation, the mere momentary notion, the slightest passing fancy of a man legally marrying another man in the 1850s or 1950s would have been scoffed at as incomprehensible. Such proponents would have been deemed certifiably insane. Public authorities might well have hauled them away as menaces to society.

These fundamental transformers did, however, seek to break down natural-traditional-biblical boundaries for family and marriage. They sought every means to reshape and redefine. They did so to the point that now, today, the Communist Party USA, the People’s World, and even Castro’s Cuba, not to mention leftist groups like the Beyond Marriage campaign, have picked up their mantle and embraced gay marriage as the vehicle to achieve what their leftist forbears were unable to achieve.

For the far left, gay marriage is the Trojan horse to secure the takedown of marriage it has long wanted, and countless everyday Americans are oblivious to the older, deeper forces at work. And even more delicious for the left, gay marriage is serving as a stunningly effective tool in attacking what the far left has always hated most: religion.

In a telling moment about a year ago, I received an email from a reader who once had been part of the “gay left.” He told me that even most gay people, who are either not political or nowhere near as political as the extreme left, have no idea how their gay-marriage advocacy fits and fuels the far left’s anti-family agenda, and specifically its longtime take-down strategy aimed at the nuclear family. The emailer is exactly right (and inspired me to begin collecting the material that led to this book).

Indeed, most of the gay people I have known are Republicans. Generally, I have had no problem easily dialoguing with them, though it is getting more difficult, as liberals have done their usual excellent job convincing an entire group that I as a conservative hate them. Even when socially liberal -- and, even then, mainly on matters like gay rights -- the gay people I’ve met have been economic conservatives, not to mention pro-life on abortion. But in signing on the dotted line for gay marriage, they have also, whether they realize it or not, enlisted in the radical left’s unyielding centuries-old attempt to undermine the family. The same is true, ironically, for “conservatives” who support gay marriage, for libertarians who worship a golden calf of “freedom” that is fully separated from faith, and for the “moderates” swimming (as they usually do) with the cultural tide.

Unlike the communists who ripped marriage as “bourgeois claptrap,” as a form of “slavery” and “vile patriarchy,” as a system of “captive housewives,” and who forcibly collectivized children into full-time nurseries in order to deliberately undermine the traditional family, the vast majority of today’s proponents of same-sex marriage have friendly motives. Their goal is not to tear down but to “expand” marriage to a new form of spousal partner. They do this with the intent of providing a new “freedom” and “right” to a new group of people. I get that. Unfortunately, there’s so much that they are not getting.

Today’s advocates of same-sex marriage need to be aware of the quite insidious deeper historical-ideological forces they are unwittingly serving. Sure, that knowledge still will likely not change their minds, but it’s something that a well-informed, thoughtful person should at least be willing to learn before urging the unprecedented action that our culture and court may be about to take.

Paul Kengor’s newly released book is Takedown: From Communists to Progressives, How the Left Has Sabotaged Family and Marriage. His other books include The Communist: Frank Marshall Davis, The Untold Story of Barack Obama’s Mentor, and Dupes: How America’s Adversaries Have Manipulated Progressives for a Century.