Weeden and Kurzban’s The Hidden Agenda of the Political Mind uses two ideal types to explain the Culture Wars: Freewheelers and Ring-Bearers.

Freewheelers include people who sleep with more people, are sexually active outside of committed relationships, have more same-sex partners, party, drink, go to bars, and use recreational drugs more, live together outside of marriage, are less likely to marry at all, get divorced more when they do marry, and have fewer kids.  Ring-Bearers include people who wait longer to have sex, tend to have sex only in committed relationships (often waiting until getting engaged or married), go to bars and party less, don’t cohabit outside of marriage, have long-lasting marriages, and have more kids.

The book then dissects the divergent interests of the two types.  The Freewheelers:

People who party and sleep around have an interest in other people not bringing legal or moral costs to bear on them for doing so.  People who want to delay having children while partying and sleeping around have an interest in the availability of family planning, including the backstop of legal abortion.  Their mental Boards of Directors will prefer moral and political policies that help them live the lives they want to live.

The Ring-Bearers:

For young Ring-Bearers, a big problem is finding suitable partners to share Ring-Bearer lives with.  Young women asking their boyfriends to wait for sex have to compete with young women offering more immediate rewards.  For both sexes, the fewer people fooling around, the more suitable candidates there are for long-term Ring-Bearer relationships.

[…]

For both Ring-Bearer men and women, the chances of maintaining a faithful marriage depend in part on what people around them are doing when it comes to low-commitment sex.  Ring-Bearers have an increased interest in minimizing temptations faced by their mates, and the fewer people fooling around, the less likely it is that one’s mate will succumb.

An obvious way to make Freewheeling less common is to make it more costly.

These are some of Weeden and Kurzban’s better just-so stories of selfishness.  But they’re still easy to improve.  For starters, as long as you’re straight (or even a straight-leaning bisexual), selfishness implies big gender splits within the Freewheeler and Ring-Bearer ideal types. 

If you’re a Freewheeling male, you should staunchly oppose legal burdens on female promiscuity.  But you should be open to legal burdens on male promiscuity.  If a policy burdens all promiscuous males other than yourself, the Freewheeling male should enthusiastically support the burdens.  For example, a Freewheeling male who can demonstrate he’s had a vasectomy has every selfish reason to ban condoms.  Why?  Because this gives him a huge competitive edge over all the fertile Freewheeling men.  The reverse goes for Freewheeling women.  As soon as they get their tubes tied, their self-interest urges them to become pro-life, giving them a competitive edge over all the fertile Freewheeling women.

Analogous results hold for Ring-Bearers.  Selfishly speaking, Ring-Bearer men should recoil to see fellow men in church; Ring-Bearer women should recoil to see fellow women in church.  Staunch Ring-Bearer men should favor secular sex education for men to reduce the supply of men competing to marry the best Ring-Bearer women; Staunch Ring-Bearer women should favor secular sex education for women to reduce the supply of women competing to marry the best Ring-Bearer men.

Once you account for these subtleties, however, Weeden and Kurzban’s original claims seem worse than over-simplified; they could be totally wrong.  Consider: Freewheeler men (a) benefit from legal burdens on men other than themselves, (b) lose from legal burdens on themselves, and (c) lose from restrictions on women.  Some legislation comes forward that combines (a), (b), and (c).  Selfishly speaking, the key question is: “What is the NET effect?”  The general answer is: “Unclear.”  This is a simple extension of what regulatory economists have known for decades: Regulated firms can and often do benefit from regulation, because differential burdens imply benefits.

Here’s an additional complexity.  Weeden and Kurzban rightly emphasize that Ring-Bearers face a painful uncertainty: Is their spouse only pretending to be a Ring-Bearer?  (This is a mild problem for Freewheelers, since they invest little in long-run relationships anyway).  Now consider: What would happen if the law persecuted anyone who openly pursued a Freewheeling lifestyle?  Freewheelers would obviously respond by acting like Ring-Bearers!  This in turn raises Ring-Bearers’ risk of accidentally marrying a Freewheeler-in-Ring-Bearer’s-clothing.  Selfishly speaking, then, Ring-Bearers actually have a strong reason to amiably tolerate their Freewheeler rivals: Libertines are a lesser evil than hypocrites.

You could protest that my predictions about Freewheelers’ and Ring-Bearers’ opinions are wrong.  But that misunderstands what I’m doing.  I’m not describing how Freewheelers and Ring-Bearers think.  I’m describing how they would think if they were self-interested.  My arguments give readers a choice: Embrace bizarre claims about public opinion, or stop claiming that self-interest explains what people think about sexual politics.