The next culture war will look very different from the old one. But whether it is about religious liberty or marriage and the family or who gets to define American identity, we can be sure of one thing: It will be fiercely fought.

The battle for same-sex civil marriage in the United States isn’t quite over, but this week may be remembered as the turning point. The Supreme Court has yet to definitively rule that it is unconstitutional for state governments to refuse to recognize the marriages of same-sex couples, yet its decision to allow various lower-court rulings to stand is a big deal. It is no longer so difficult to imagine that in the next few years, the Supreme Court will find that there is a constitutional right to same-sex civil marriage that applies as much in Alabama as it does in Massachusetts.

The stunning collapse of mainstream opposition to same-sex marriage represents the end of what has proved to be a short chapter of the culture war—after all, we’re only 11 years from the Goodridge decision that allowed same-sex civil marriage in Massachusetts. So what will self-styled progressives and self-styled traditionalists battle over next?

Even if same-sex marriage becomes the law of the land, we’re not about to stop debating it. Gary Bauer, the former Republican presidential candidate, points in a recent Washington Examiner op-ed to the fact that at least one survey, from the Pew Research Center, finds that support for same-sex marriage may have peaked, having fallen 5 percentage points since February to 49 percent. This could be a blip, or it could be the start of a backlash. Moreover, it remains unclear if the success of the marriage equality movement will have some larger effect on how Americans think about marriage. David Blankenhorn of the Institute for American Values famously reversed his opposition to same-sex marriage on the grounds that we should be encouraging everyone to enter into long-term, sustainable relationships. Instead of devoting time and effort to keeping same-sex couples out of the institution, he wanted to rally them to the cause of reviving marriage for all Americans, particularly the poor and working-class Americans who are far less likely to be in stable marriages than their affluent and educated counterparts.

Some conservative critics, like Ryan Anderson of the Heritage Foundation, argue that the rise of same-sex marriage represents the triumph of the misguided belief that consenting adults should be free to form any kind of relationship they choose. Anderson and his allies instead defend what they call the “conjugal view” of marriage, in which marriage is understood as permanent, exclusive, and rooted in the ways women and men are distinct and complementary. If marriage is redefined as an emotional union first and foremost, Anderson warns, there is no principled basis on which to oppose future redefinitions of the institution. Last year in Slate, for example, Jillian Keenan made the case for legalizing polyamory. You could also imagine the rise of advocates for temporary marriage, or other variations on the institution. There could be some cleavage, then, in the big tent of same-sex marriage supporters, with some joining Blankenhorn in making the case for monogamous marriage and others calling for moving beyond its strictures.

A closely related possibility, widely feared among social conservatives, is that the winning side in the same-sex marriage debate won’t prove magnanimous in victory. As the number of religiously unaffiliated Americans continues to grow, a new, more explicitly anti-religious strain of progressivism will emerge. America has never had an anti-clerical politics as such, as the United States has never had an established church of the kind found in Europe. Even as religious observance has declined, the American consensus in favor of the accommodation of religious belief has for the most part endured. Now, however, there are indications that appeals to religious liberty are losing their resonance for secular liberals.

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