When the California Supreme Court created a “right” to gay marriage last week, it was entirely foreseeable that opponents of the ruling would organize. For the second time in eight years, Golden State voters will most likely have the opportunity to weigh in on whether to define marriage in California as between a man and a woman.

The response to the court’s decision – positive in many quarters – drove home the hard fact that traditionalists are losing the battle of both language and ideas in the public square. It’s becoming increasingly difficult for gay marriage’s opponents to convince their fellow citizens that the institution of marriage is best reserved for those with the putative ability to conceive, bear and raise children together.

If they are to make that argument successfully, traditionalists must understand that they’re not just grappling with the issue of gay marriage. They’re confronting an increasingly entrenched consensus that “private” sexual behavior is always just an individual matter about which society properly has no opinion – the logical result of a culture that, too often, confuses moral relativism with tolerance. And they’re challenging a host of social and ideological transformations that were set in motion long before this controversy arose – whose influence shapes the debate over gay marriage in particular, and sexual morality in general.

As strange as it seems, it all began with the pill. Decades ago, the invention and ready availability of reliable birth control successfully decoupled childbearing from sex. Certainly, in many ways, this development represented a welcome liberation for women, enabling them to exercise control over their own reproductive capacities and plan their own futures. But unforeseen consequences accompanied that benefit. Most notably, completely divorcing the sex act from the potential for procreation converted sex into just another recreational activity.

In turn, the establishment of “sex as recreation” led to the decoupling of sex from marriage. Since sex was fun – and one could protect against an unplanned pregnancy both through contraception and abortion on demand – there was no real reason to be married in order to do it. With that, couples who wanted to have sex (despite, perhaps, not knowing or even liking each other) felt free to do so.

But “accidents” happen. Women get pregnant. And the same couples who had been eager to go to bed together decided that they didn’t really have enough in common to justify marrying, notwithstanding the impending birth of the child they had created. With empathy (and, perhaps, a measure of respect for the mothers who chose not to abort), the larger culture refrained from criticizing unwed mothers; elites even celebrated their “choice” to rear children on their own (as those who remember the “Murphy Brown” brouhaha can attest). The fallout – rampant illegitimacy, child poverty, boys deprived of an example of what it means to be “manly,” and girls so starved for male affection that they’ll give up their bodies to any man who asks – is apparent.

With cultural precedents establishing that marriage is irrelevant both to sexual activity and to childbearing (or –rearing), traditionalists now find themselves in the awkward position of trying to explain why it should, nonetheless, be off limits to gays. To complicate things further, activist judges have arrogated to themselves the power to resolve the foundational issue underlying the entire debate: Whether a society still has the right to codify its collective beliefs about sexual morality in its laws. By finding a constitutional right to consensual homosexual conduct in Lawrence v. Texas, the Supreme Court has, in effect, suggested that it does not – that such decisions are properly made only at the individual level.

Apparently, the California Supreme Court agrees. In fact, the reasoning enshrined in the California Supreme Court’s ruling last week could be applied just as validly to a whole host of hitherto-unimagined (and unimaginable) intimate relationships.

Whatever the ultimate outcome on the issue of gay marriage in California, this is only latest in a series of skirmishes over whether there are limits to state-sanctioned sexual behavior in America. If the traditionalists are going to have any hope of prevailing in the marketplace of ideas, they will first have to find a way to explain to an ordinary American why, sometimes, “private” sexual behavior is, in fact, everyone’s business.