It was time, once again, for a political leader to step to the microphone and debate the politics of morality with America's most outspoken Roman Catholic prelate.

This time, Cardinal John O'Connor had used his pulpit in St. Patrick's Cathedral to deliver a diplomatic, but forceful, sermon attacking a New York City Council plan to create "domestic partnerships" equal to marriages. After quoting centuries of secular and sacred texts, he stressed that the church believes unconditionally that "no human authority can make any other state of life equivalent to marriage."

To which Mayor Rudolph Giuliani could only respond: There he goes again.

"You know, we have a division of church and state in the United States and it's a healthy one," the Republican mayor, who is a Catholic, told reporters in a press conference later in the day. "We're all here because people left other places because someone wanted to enforce their religious viewpoint as the view of the state."

And one more thing, noted Giuliani: "Domestic partnerships not only affect gays and lesbians, but they also affect heterosexuals."

Ironically, O'Connor and Giuliani were in totally agreement on this latter point. The cardinal's seven-page homily -- the printed text was provided for reporters -- included no direct references to homosexuality. The closest he came to mentioning this hot-button subject was to say that traditional moralists who have examined the domestic partnership proposal have "understandably raised questions about the morality of extramarital genital relationships, whatever the sex of the parties involved."

When religious traditionalists wade into public debates about sexuality, yet strive to avoid references to homosexuality, gay community leaders often accuse them of trying to hide their homophobia by using an ecclesiastical code. This tension reveals a truth that is rarely discussed during heated sex debates in American pews and public institutions. While it's true that the Bible contains relatively few verses that clearly forbid homosexual activity, it contains page after page of references to marriage and extra-marital sex.

This makes the stakes in public debates over "marriage" even higher than they are in clashes over the legal and moral status of homosexuality. It's impossible for anyone, on either side of the aisle, to discuss one issue without raising the other. All roads lead to a political land mine -- the definition of marriage or any new state of life that takes its place. This then affects the meaning of the word "family."

Looking down from their pulpits, and far into the future, the cardinal and other religious conservatives should be able to do the math -- for every same-sex domestic partnership there will almost certainly be dozens of state-sanctioned semi-marriages for heterosexual couples.

It would be impossible to raise an issue that touches more men, women and children, said O'Connor. As Pope John Paul II has written: "The family is the 'first and vital cell of society.' It is from the family that citizens come to birth and it is within the family that they find the first school of the social virtues that are the animating principle of the existence and development of society itself."

The changes that are sweeping through cities such as San Francisco and New York will inevitably lead to similar disputes elsewhere. Right now, noted the cardinal, marriages performed in New York City are recognized as valid in the rest of the state and in other states. It is natural to ask what status new "domestic partnerships" will have elsewhere. This question then leads to others, such as: What happens when these vague unions end?

"A spouse has a right to support from the other spouse," said O'Connor. "Will a domestic partner have to provide support? A spouse has certain rights with regard to property. What would be the case in domestic partnerships? What would be the legal effect on children? What of the question of filing joint tax returns, pension rights, etc.?"

Out in the pews, others must have been thinking of another question that looms just ahead: What are the rights of domestic grand partners?