Justice Anthony Kennedy’s announcement that he will retire this summer in time to allow President Trump to pick his successor seems like as good an excuse as any to say that, in my view, the long arc of the moral universe bends towards endless grinding culture war without clear winners or resolution.

The reason, as I see it, is that there are countervailing treatment and selection forces that push towards both social liberalism and social conservatism in the politics of Western countries, and both types of forces are growing in strength rather than relenting.

The side pushing towards social liberalism has been explored more thoroughly, perhaps; as recently as mid-2016, in the hazy afterglow of the Obergefell gay marriage decision and in the heyday of the “Transgender Triumph” you would read essays like this from Mark Tushnet of Harvard Law School, stating that “The culture wars are over; they lost, we won,” and urging a merciless attitude with defeated conservatives. Conservatives around the same time generally agreed that they had lost: Albert Mohler, president of the Southern Baptist Theological Seminary, “We are on the losing side of a massive change that’s not going to be reversed, in all likelihood, in our lifetimes.”

The reasons for the advance of social liberalism are many, but a few that stand out would be a steady increase in cosmopolitanism as communications and culture become more global, a retreat from sexual stricture and heterosexual marriage thanks to birth control, abortion, and better employment prospects for women, the demographic shift in Western countries away from white Christians, and the general pattern of societies to become more liberal as they become more affluent and educated- what Robin Hanson has called the replacement of farmer morality with forager morality. On top of all of those, I suspect that the technology of social media itself tends in the main to select for socially liberal attitudes, that there are intrinsic reasons why those attitudes are the ones that are most effectively viral.

A key thing to note is that none of these forces has significantly abated in the last few years. In fact, in the main, they have become stronger. Democrats express much more cosmopolitan and racially progressive attitudes than they did just recently, while Republican attitudes have if anything moved in the same direction:

Getting married tends to make women in particular more conservative, and the retreat from marriage among young women in particular has become near-asymptotic:

Having babies also tends to move women to the right, and we are approaching a historic low in American fertility:

It’s perhaps no surprise then, for these and other reasons, that current polling suggests an unprecedented gender gap in political preferences of young Americans; while older Boomer men and women more or less have identical voting intentions, Millennial men are +3 Republican and Millennial women an astounding +44 Democrat:

So why, given these trends, not expect liberal triumph- if not 2016 as predicted, then sooner or later? One set of answers popular among American liberals for their recent struggles is institutional. The design of American government- the electoral college, Senate, Supreme Court, and various layers of local and state government were created in order to preserve the privileges of white male property owners, it is said, and these institutions largely succeed in this goal. Mitch McConnell’s Senatorial defeat of Merrick Garland’s nomination to the Supreme Court and substitute of of Neil Gorsuch after an electoral college victory (and popular defeat) by Trump is, to many liberals, an exemplary instance of multiple designed-to-be-conservative institutions conspiring to defeat progressive popular will.

But left and liberal parties are in the retreat across Europe as well as in the United States, suggesting that the particularities of US institutions can’t be the only thing at work.

Another proposed reason for the apparent retreat of liberalism, exemplified by Patrick Deneen’s Why Liberalism Failed, suggests that Liberalism lost by winning, that it ran into intrinsic limits to the human desire for individual autonomy, self-expression, and freedom versus belonging and group identity, that once you get to the End of History you can’t go any further along the same path. While I’m sympathetic to this view, I think it ignores that along many dimensions we really are in a more conservative time than the 60s, 70s, and 80s, that many things have moved right even if Cthulhu would prefer to swim left.

So let’s take one more step back and point out that demographic change is not just about race. The sexual revolution, heredity, and politics are a continuing story, and changes in reproductive technology may have opposing selection and treatment effects: it’s likely that technologies to suppress reproduction make culture (women in particular) more liberal-but if more liberal women opt into these technologies, they also make the electorate more conservative in the long run.

The young people who are currently entering voting age (18 year olds born around 2000), not only were conceived at time when abortion and birth control were widely available, but their parents were conceived on average at a time when abortion and birth control were widely available, a two generation selection effect, large enough to be detected.

Indeed, political gaps in fertility for the parents of kids currently entering voting age were very large, much larger than pre-sexual revolution.

Another picture of the same relationship: for women in their 40s by decade of the General Social Survey, the relationship between number of children (y axis) and self reported ideology (1- Extremely liberal to 7- Extremely conservative, x-axis) has becomesteadily stronger over time:

Not only is self-reported ideology strongly associated with fertility, self-reported promiscuity is now strongly associated with fertility’s absence. This going to have effects sooner or later on genetic predispositions with political effect.

This is most obvious among rapidly growing religious groups like the Amish and ultra-Orthodox Jews, but is also suggestive of why, for example, average American religious observance has barely declined across many decades, if anything returning to a pre-1950s baseline rather than falling ever lower:

To go by a large survey of high school students’ 2016 Presidential preferences conducted by the Hispanic Heritage Foundation, the conservatizing trends in demographics are already manifest among “Generation Z” teenagers, at least compared to Millennials; on the other hand, these kids haven’t yet gotten to college and in any case there’s a difference between a poll and a vote.

The culture war is perhaps most centrally about who is born and who is not, about who becomes parents and who does not. Freedom from parenthood is in some ways a source of cultural strength these days- there’s a reason pretty much all the heads of state running Western Europe right now don’t have any kids- but the future as is often said belongs to those who show up.