A coalition of Catholic and Protestant leaders has united to call all Christians to an unwavering defense of the truth of marriage, rooted in nature as well as faith.

"(W)e affirm strongly and without qualification, following the clear testimony of Holy Scripture, that marriage is a unique and privileged sign of the union of Christ with his people and of God with his Creation – and it can only serve as that sign when a man and a woman are solemnly joined together in a permanent union," reads a joint statement between Catholic and Protestant leaders.

"If we are to remain faithful to the Scriptures and to the unanimous testimony of Christian tradition, there can be no compromise on marriage."

Nearly 20 Catholics and Evangelical Protestants signed the statement, which is titled "The Two Shall Become One Flesh: Reclaiming Marriage." Signatories represent the ecumenical coalition Evangelicals and Catholics Together (ECT), which is an initiative of the Institute on Religion and Public Life.

The statement will debut in the March issue of "First Things" magazine.

"(M)arriage is the foundation of a just and stable society," the Catholic and Protestant leaders said, emphasizing that marriage was a reality that existed before the state.

The truth about marriage can be found in "both revelation and reason," they said, pointing to both Scripture and "the truths inscribed on the human heart."

However, the sexual revolution has gravely weakened marriage, they continued, pointing to decreasing marriage and birth rates, as well as rising abortion and divorce levels in the past 50 years.

"A contraceptive mentality encourages the notion of sex as purely recreational, a matter of private pleasure. Widespread divorce and serial cohabitation undermine our sense of stability and commitment in human relations," they said, also noting an increase in out-of-wedlock births and casual acceptance of premarital sex.

"Christians are implicated in this decline. Evangelicals and Catholics are more likely to divorce than they were fifty years ago. Moreover, Christians have adopted to no small extent the contraceptive mind-set that in society at large has separated sex from reproduction and so weakened the centrality and attraction of marriage."

Everyone suffers from this modern marriage crisis, the statement explained, but especially children and those with lower education levels.

Redefining marriage poses a particularly dangerous threat to society and the common good, said the Catholic and Protestant leaders.

Same-sex "marriage" is now legal in more than 30 states and the District of Columbia. The U.S. Supreme Court announced earlier this month that it would take up the issue of same-sex "marriage" again this term.

For those who experience same-sex attraction, the signers of the statement encouraged the search for genuine freedom in God's truth. They also apologized for any injustices to persons with same-sex attraction and promised to better integrate all single people into the life of the Christian church.

"However, faithful Christian witness cannot accommodate itself to same-sex marriage. It disregards the created order, threatens the common good, and distorts the Gospel," they said.

When marriage is redefined, they explained, "the distinction between men and women is denied social recognition and marriage is no longer a unique bond uniting male and female. It becomes an instrument created by the state to give official status to the relationship between two generic human beings."

The result is a "parody of marriage" that reconfigures the basic family structure and the natural family as the "fundamental context defining where we have come from."

The signatories also warned of other consequences stemming from a redefinition of marriage.

"(W)here the family is a creation of the state, children become, in important legal respects, the property of the state," they explained.

Furthermore, when we deny truths about human nature, we lose sight of our fundamental dignity as children of God, they cautioned: "If the truth about marriage can be displaced by social and political pressure operating through the law, other truths can be set aside as well."

The stakes are therefore high, for all of society, the Catholic and Protestant leaders stated.

"Freedom itself is severely compromised when our speech about the difference and complementarity of male and female must be policed, and any dissent from the new orthodoxies assiduously suppressed."

"It is increasingly difficult to affirm that marriage is the union of a man and a woman without being ruled outside the boundaries of reasonable public conversation," they observed. "And once opposition to same-sex marriage is judged to be discriminatory, no institution that declines to substitute unreality for reality will remain unaffected."

Reclaiming true human sexuality is key to healing a broken culture of marriage and escaping the false views that amount to a degrading and deceptive "pseudo-freedom," the religious leaders said.

Rather than going along with the spirit of the age, they encouraged Christians everywhere to take a strong stand on marriage.

"We owe our fellow citizens a socially engaged witness to the truth about marriage, which, with the family, is the unalterable foundation of a healthy, humane society."