Just 16 years after a Democratic president signed the fatuously named Defense of Marriage Act,
defining marriage in the U.S. as requiring one man and one
woman, the debate over gay marriage is over.

Isn’t it? Even though DOMA is still on the books, even
though most states that have voted on the issue have voted
against same-sex marriage, all the energy is in the opposite
direction. What seemed at first like a bizarre idea has become
utterly conventional. By judicial decree interpreting the state
constitution, by act of the legislature and someday soon by
popular referendum, one state after another is falling. Same-sex
marriage is legal in Canada.

Does anybody believe that five years from now it will be
harder than it is today for two women or two men to marry? It’s
no longer all that hard today. I suspect — don’t you? — that
even many anti’s have given up in their hearts and have resigned
themselves to taking comfort in one more example of how the
country is going to hell.

“What’s next?” opponents of same-sex marriage have
sometimes asked, they thought rhetorically. If a man can marry a
man, what about a man marrying two men? Or two mixed-sex couples
merging into a married foursome? Or — the inevitable reductio
ad absurdum — why shouldn’t a man marry his German shepherd if
he wants to?

What’s Next

No doubt these opponents enjoyed (and deserved, actually) a
warm I-told-you-so moment over a recent headline in the New York
Times: “Measure Opens Door to Three Parents, or Four.” It was
about a bill in the California Legislature — California! Home
of the famous Proposition 8, a successful ballot initiative to
outlaw same-sex marriage — to allow adoptions by more than two

The bill is about parenting, not about sex. (Even in
California, there are only two sexes, approximately.) But the
bill recognizes the reality of unconventional families: divorced
dads who want to keep a close relationship with their kids,
lesbian couples who want to adopt each other’s children, and so

And the opponents of gay marriage are right. Once that
initial wall is breached, a lot of this suddenly seems to make
perfect sense. Where they’re wrong is to think that this is a
good argument against same-sex marriage. Every big societal
change carries more change in its wake. And every change is a
revolution in perceptions. From the present, you look back 20
years and think, “Why did we find the idea of same-sex marriage
so weird?” Twenty years from now, gay marriage will be so common
that people might be forgiven for thinking that the Defense of
Marriage Act was passed to protect gay marriage.

This is one good reason for reserving some sympathy for
those who aren’t wholly onboard as the train of change comes
whistling through: There is something you think today that will
seem preposterous and even offensive to your 20-years-from-now
self, if you’re still around. Some injustice that will seem
obvious, although right now we can’t see it at all. What will it
be? It would be nice to get a heads up.

“Not every disputed institution or practice is destined to
be discredited,” the Princeton philosopher Anthony Appiah wrote
a couple of years ago. Looking back, he contrasted abolition (a
cause that came “to represent moral common sense”) with
Prohibition (a cause eventually seen as “quaint or misguided.”)

Appiah suggested three signs of a practice that seems
harmless today but will seem indefensible tomorrow (or,
presumably, vice versa). First, “a particular practice is
destined for future condemnation” if the argument against it has
been building for a while. “The case against slavery didn’t
emerge in a blinding moment of moral clarity.” Second, the
defenders of current practice “invoke tradition, human nature or
necessity” rather than morality. Third, the defenders engage in
“strategic ignorance.” We might say they are in denial about
“the evils in which they’re complicit.”

Four Nominees

Today’s prohibitionists and abolitionists are already
working on some issue that will look completely different to
most of us two decades from now. What is it? Appiah has four

— Prisons. We incarcerate more of our population than any
country in the world. Jokes about prison rape are staples of
American comedy. In 20 years, we may look back in amazement that
people would think this was funny.

— Industrial farming. The longstanding discussion of the
conditions under which animals are grown for food is turning
into a discussion of the morality of using other animals for
food at all.

— The elderly. Baby boomers already feel guilty about how their parents spend their last years. Just wait until it’s the
boomers’ turn.

— Greenery. Environmental degradation is a debt to our
children that parallels the debt to our parents.

My own favorite nominee will win me no friends: high school
football. In 20 years I think it may seem incredible that loving
parents used to send their kids out to bang their heads against
one another in the certain knowledge that this was damaging
their still-growing brains. “Certain knowledge” may overstate
the case now. But this smells just like smoking, about which the
evidence dribbled in until it was undeniable. Let me add (for my
own self-protection): I hope I’m wrong.

Suggestions from colleagues ranged from weighty moral
issues to relatively trivial rules of grammar. In two decades,
will it seem incredible that people in 2012 were generally
unconcerned about the military use of drones? That we didn’t
have a national identity card? That Americans regularly and
unapologetically used “which” when we should have used “that”
(or vice-versa)?

One colleague suggested “free wireless.” Does he mean that
we will be amazed that anybody paid for an Internet connection
as recently as 2012, or that anybody thought they could have it
for free?

Same-sex marriage is not yet universally accepted. But it’s
not too soon to start looking for the next sea change. What will
it be? Leave your nominations in the comments below or post them
to Twitter using the hashtag #headsup.

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Michael Kinsley

Michael Kinsley is a Bloomberg View columnist.