I agree with the President and the pope: Marriage is a very serious endeavor, not to be trifled with. Just ask any of the tens of millions of divorced parents who are tied together for life in a precarious, often combative attempt to raise their kids well in separate households.

Done right, marriage–or “civil unions” if the M-word is too loaded–can be a bridge to loyalty, sexual stability, shared financial responsibility and the more efficient rearing of children. All the more reason, then, to support anybody, gay or straight, who wants to commit to a lifelong union. Whether you are united in “holy matrimony” or simply trying to build a lasting relationship should be of no concern to the state, nor should your sexual orientation.

Where I differ from the President and the pope is in defining marriage in religious terms. Under the US Constitution, after all, church is clearly separated from state, and thus marriage is a civic institution not in any way requiring the participation of religious organizations. Government policies favor the family unit. If the state is offering special rights and benefits for those couples who marry, then to exclude gays is simply unconstitutional.

In Germany, France, Canada and Vermont, state-sanctioned unions help gay couples clarify the legal status and rights of their partnership in everything from bank accounts to hospital visitation to child custody. For gays seeking these rights elsewhere, this is primarily a practical struggle, and it is wrong for the President to exploit it for political purposes.

The drive for gay marriage is also an affirmation of responsible love, and it is bizarre that this honorable impulse could be blocked on the basis of someone else’s religious views. The desire of two people to commit to some shared order in their lives, presumably reinforcing notions of sexual monogamy, has particular relevance in the gay community, which has paid an enormous price for promiscuity. It is also a community riven by the loss of loved ones in which a partner’s rights to share in managing grief have been painfully challenged when a mate faces death.

It is one thing for the pope, a religious leader, to oppose gay marriage based on the theology that “homosexual acts go against the natural moral order.” But the President of the United States, as the highest official in our secular government, is overstepping his bounds mightily when he lectures about “sin” and “the sanctity of marriage.”

“I believe a marriage is between a man and a woman. And I think we ought to codify that one way or another,” Bush said last week, seizing upon a question about homosexuality that didn’t mention marriage. “And we’ve got lawyers looking at the best way to do that.”

Well, lawyers can do just about anything with the law to make their case, but it is hoped that most judges will have read the Constitution and seen that it says nothing about merging church and state.

What the President didn’t mention was that the US high court finally has acknowledged that homosexuality is not a threat to public order, striking down discriminatory anti-sodomy laws in Texas.

If homosexual sex is legal, it doesn’t matter if our born-again President believes it’s a sin on the grounds that it offends his or anyone else’s interpretation of Christian Scripture.

Ironically, in the same press session in which Bush acted as if our nation is a Christian theocracy, he applauded Iraq’s faltering steps toward a secular society that would break with Islamic dictates. He even mentioned the prospect of an Iraqi Thomas Jefferson emerging to show those folks how to go about building a free society.

But Jefferson was an awkward choice for Bush because he was as responsible as any of the founders for the very notion of the separation of church and state. As a public man, Jefferson even resisted identifying himself as Christian, being, as he wrote, “averse to the communication of my religious tenets to the public because it would seduce public opinion to erect itself into that inquisition over the rights of conscience, which the laws have so justly proscribed.”

And, as the Supreme Court has clearly stated, being gay, even in Bush’s home state of Texas, is one of those rights of conscience.