Advocates of same-sex “marriage” present the idea as a step forward for tolerance and respect. But recent developments place that interpretation very much in doubt.

Legalizing same-sex “marriage” is not a stand-alone policy, independent of all the other activities of the state. Once governments assert that same-sex unions are the equivalent of marriage, those governments must defend and enforce a whole host of other social changes.

Unfortunately, these government-enforced changes conflict with a wide array of ordinary liberties, including religious freedom and ordinary private property rights.

It began with the persecution of Catholic Charities in Boston. The archdiocese eventually closed down its adoption program, because the state of Massachusetts insisted that every adoption agency in the state must allow same-sex couples to adopt.

Recently, a Methodist organization in New Jersey lost part of its tax-exempt status because it refused to allow two lesbian couples to use their facility for a civil union ceremony. In Quebec, a Mennonite school was informed that it must conform to the official provincial curriculum, which includes teaching homosexuality as an acceptable alternative lifestyle.

At last report, the Mennonites were considering leaving the province rather than permit the imposition of the state-sponsored curriculum on their children.

And recently, a wedding photographer in New Mexico faces a hearing with the state’s Human Rights Commission because she declined the business of a lesbian couple. She didn’t want to take photos of their commitment ceremony.

The underlying pattern is unmistakable. Legalizing same-sex “marriage” has brought in its wake state regulation of other parts of society. The problem is sometimes presented as an issue of religious freedom, and so, in part, it is. But the issue runs deeper than religious freedom.

McGill University professor Douglas Farrow argues in his book A Nation of !@#$% that redefining marriage allows the government to colonize all of civil society.

If same-sex couples can marry each other, they should be allowed to adopt. Anyone who says otherwise is acting against the policy of the state. If same-sex couples can have civil unions, then denying them the use of any facility they want for their ceremony amounts to unlawful discrimination. When the state says that same sex couples are equivalent to opposite-sex couples, school curriculum will inevitably have to support this claim.

Marriage between men and women is a pre-political, naturally emerging social institution. Men and women come together to create children, independently of any government. The duty of caring for those children exists even without a government or any political order.

Marriage protects children as well as the interests of each parent in their common project of raising those children.

Because marriage is an organic part of civil society, it is robust enough to sustain itself, with minimal assistance from the state.

By contrast, same-sex “marriage” is completely a creation of the state.

Same-sex couples cannot have children. Someone must give them a child or at least half the genetic material to create a child. The state must detach the parental rights of the opposite-sex parent and then attach those rights to the second parent of the same-sex couple.

The state must create parentage for the same-sex couple. For the opposite-sex couple, the state merely recognizes parentage.

In her essay in The Meaning of Marriage, Seana Sugrue argues that the state must coddle and protect same-sex “marriage” in ways that opposite-sex marriage does not require.

Precisely because same-sex unions are not the same as opposite-sex marriage, the state must intervene to make people believe (or at least make them act as if they believe) that the two types of unions are equivalent.

Public schools in California are soon going to be required to be “gay friendly.” A doctor has been sued because she didn’t want to perform an artificial insemination on a lesbian couple. A private school is in trouble for disciplining two female students for kissing. All in the name of supporting the rights of same-sex couples to “equality” with straight couples.

The fact that opposite- and same-sex couples are different in significant ways means that there will always be scope for the state to expand its reach into more and more private areas of more and more people’s lives.

Perhaps some people think it is okay to shut down Catholic adoption agencies, because the Catholics have it coming to them: The Church’s enemies are many. Perhaps some people don’t care for Methodists, and don’t care whether they lose their tax-exempt status.

But the Mennonites? These are the most inoffensive people on the planet. They have been pacifists for centuries. Their continued existence here in North America is a testimony to the strength of our ideals of religious tolerance and pluralism, in all the best senses of those terms. But now, in the name of equality of same-sex couples, the Mennonites are being driven out of Quebec.

Perhaps you think people have a natural civil right to marry the person of their choosing. But can you really force yourself to believe that wedding photography is a civil right?

Maybe you believe that same-sex couples are entitled to have children, somehow. But is any doctor they might encounter required to inseminate them?

Advocates of same-sex “marriage” insist that theirs is a modest reform: a mere expansion of marriage to include people currently excluded. But the price of same-sex “marriage” is a reduction in tolerance for everyone else, and an expansion of the power of the state.

Jennifer Roback Morse is the senior fellow in economics at the Acton Institute and the author of Love and Economics: It Takes a Family to Raise a Village, newly reissued in paperback.