CPAC has a long history of being a showcase for conservatism’s brightest stars and most important priorities. Yet the inclusion of organizations that are working to undermine core conservative principles, even as sponsoring members of the event, has resulted in many longtime participants withdrawing from this year’s CPAC.

A clarification: Conservatism is a philosophy grounded in the affirmation that transcendent truth is immutable, that persons are created with dignity and certain natural rights, and that government’s duty is to protect both individuals and the rights endowed to them by their Creator.

Conservatism also argues that man is fallen and finite and, thus, that attempts to recreate Eden are not just immodest but doomed to failure — and that when governments usurp the transformative role of God, liberty is crushed and brutality ensues. The dictatorships of the last century are vivid and tragic cases in point.

Consequently, conservatives believe in preserving and strengthening the institutions that best advance a just, prosperous, and safe society. The pre-governmental institutions of marriage, family, church, and local community are foundational. When they are attacked, all of society suffers.

That they are under attack is indisputable. Sadly, some self-professed conservatives attack them from within — which brings me to why Family Research Council has once again chosen not to participate in CPAC.

Organizations promoting a number of anti-family issues are now participating in CPAC. For example, ample research reveals the harmful affect that decriminalized gambling has had on the family, yet CPAC has become a platform for those who want to extend the reach of gambling with the government’s blessing, while also expanding government taxation of the Internet in unprecedented ways.

Additionally, promoting the legalization of illicit drugs discourages an environment where families and communities prosper. Yet CPAC has chosen to permit advocates of this destructive social change to help lead the event.

Finally, and most illustrative of our concerns, is the inclusion of organizations in the drafting of the CPAC agenda whose stated objective is to impose a radical redefinition of marriage on America. A few years ago it was the ACLU, and today it is a group that defines itself by its sexual affinity. Sadly, this makes it clear that CPAC has lost its way.

The inclusion of GOProud as not only an exhibitor but as a member of the planning committee indicates a fairly obvious effort to “mainstream” an organization whose commitment to overturning the historic prohibition on homosexuals in the military, the Defense of Marriage Act, and state laws against same-sex marriage is the reason for its existence.

When you combine this drift away from recognized conservative principle with well-known allegations of financial impropriety that only recently became public knowledge, you see why FRC, the Heritage Foundation, the American Family Association, the American Principles Project, and many other longtime CPAC participant organizations have withdrawn from CPAC. Our dispute with CPAC is not about the specifics of tax policy, entitlement reform, or the Colombian trade accord. It is about something far more important: the very foundation of a just and civil society.

Marriage is the union of one man and one woman, for life. Its fundamental purpose goes beyond the joining of two hearts and minds, but through that union it is designed to give life to a new generation. As the distinguished scholar Nancy Pearcey wrote last month in The Daily Caller:

Biologically, physiologically, males and females are clearly counterparts to one another. The male sexual and reproductive anatomy is obviously designed for a relationship with a female, and vice versa. Homosexual practice thus requires individuals to contradict their own biology. It disconnects a person’s sexuality from his or her biological identity as male or female — which exerts a self-alienating and fragmenting effect on the human personality.

The demand by GOProud and other homosexual activists to legalize homosexual marriage undermines the institution of marriage, in that it insists that consent and affection are the only two criteria for marriage. In doing so, GOProud joins with its liberal homosexual allies in opening the door for all manner of unions (polyamory and polygamy, for example) premised on the same criteria, and calls on conservatives to accept a definition of marriage that is intrinsically illogical and defiant of rudimentary biology.

The empirical data are replete with one essential finding: Children need a mom and a dad, each of whom brings a unique, innate set of qualities to both marriage and child-rearing. As my FRC colleague, sociologist Dr. Pat Fagan, notes, “the overwhelming majority of social science data supports the premise that the intact married family that worships weekly is the greatest generator of human and social goods and the core strength of the United States.”

The erosion of marriage is a crisis. No-fault divorce laws and a culture that lauds promiscuity and the availability of abortion-on-demand have almost unimaginably accelerated social decay. Marriages and the families they create need support, not continued assault — especially not from within the very movement that purports to defend them.

Similarly, despite clear evidence confirming that homosexuality will erode unit cohesion and military readiness and repeated warnings by current members of the Joint Chiefs, respected retired military leaders, and — most importantly — service personnel serving in the field, the Obama-Pelosi-Reid Democratic leadership eked out legislation in the final days of the last Congress that repealed the prohibition on open homosexuality in the military.

This repeal was not based on the security needs of the nation but on a political agenda pursued aggressively by one of the core constituencies of the Democratic Party, and a sponsor of CPAC — homosexual activists who want their sexual behavior to be actively affirmed in every sphere of the American experience.

In our representative form of government, open but civil debate is essential. FRC has and will continue to defend and advance these core conservative principles in the broader culture. However, it is unreasonable and self-defeating to suggest these conservative principles are open for debate within the conservative movement.

Any group that purports to be conservative should not attempt to destroy the foundations of conservatism itself, and we will not aid and abet such groups by partnering with them.

Attacking both marriage and the military is a blunt-edged assault on the two institutions that, with churches and synagogues, compose the superstructure of our national life. On them hang the future of our children, our economy, and our security. On these things, true conservatives must never waver nor compromise.

Tony Perkins is president of the Family Research Council, a group that advocates for faith, family and freedom nationwide.