The year 2012 is shaping up as a big one for same-sex marriage. Last week, the Washington state Legislature passed a bill allowing gay marriage, and legislatures in Maryland and New Jersey may follow suit shortly (though New Jersey Gov. Chris Christie has promised a veto). North Carolina and Minnesota are conducting referendums this year on constitutional amendments to bar gay marriage, and Maine is likely to conduct a referendum on legalizing it.

On Tuesday, the U.S. 9th Court of Appeals reminded us that courts too have something to say on the subject. In a case challenging the constitutionality of California’s Proposition 8, that court ruled in favor of gay marriage. Because its ruling was so narrow that it may not be applicable outside California, theU.S. Supreme Court may decide not to review this decision. Eventually, though, the Supreme Court will take a gay marriage case. How might the justices decide it when they do?

As recently as seven or eight years ago, there might not have been a single justice prepared to declare a federal constitutional right to same-sex marriage. Opinion polls then showed that Americans opposed gay marriage by a 2-1 margin, and a Massachusetts court decision declaring a right to gay marriage under the state constitution produced an enormous political backlash in 2004, with 13 states enacting constitutional bans. Even liberal justices such as Ruth Bader Ginsburg andStephen G. Breyer, who probably sympathize with gay marriage, might well have been wary of venturing too far in advance of public opinion and stoking further political backlash.

The situation has since changed dramatically. Opinion polls now consistently show that a slender majority of Americans support gay marriage. State supreme courts in California, Connecticut and Iowa have ruled in its favor, and legislatures in five states have enacted gay-marriage statutes. If liberal judges on state supreme courts now regularly support gay marriage, liberal justices on the U.S. Supreme Court are likely to do so as well.


A number of constitutional issues today — abortion, affirmative action, campaign finance reform and the death penalty — divide the Supreme Court 5 to 4, with Justice Anthony Kennedy providing the critical swing vote. How might Kennedy approach the gay-marriage issue?

Kennedy often converts dominant social mores into constitutional commands to bring outlier states into line with the majority. In this case, the states that allow gay marriage are in a distinct minority, suggesting he might be reluctant to identify such a constitutional right.

On the other hand, Kennedy has written the court’s only two decisions supporting gay rights, and he comes from a part of the country — Northern California — where support for gay marriage is strong. Moreover, Kennedy seems especially attuned to his historical legacy, and if gay marriage is inevitable, then a court ruling in its favor will probably be seen one day as the Brown vs. Board of Education of the gay rights movement.

Why is gay marriage inevitable? First, the basic insight of the gay rights movement over the last four decades has proved powerfully correct: As more gays and lesbians have come out of the closet, the social environment has become more gay friendly. In turn, as the social environment has become more hospitable, more gays and lesbians have felt free to come out of the closet. This social dynamic is powerfully reinforcing and unlikely to be reversed.


One factor that most strongly predicts support for gay equality is knowing someone who is gay. As more gays and lesbians come out of the closet, more parents, children, siblings, friends, neighbors and co-workers know or love someone who is gay. Because few people favor discrimination against those they know and love, every gay person coming out of the closet creates more supporters of gay equality.

The number of Americans reporting that they know somebody who is openly gay tripled between 1985 and 2000, reaching 75%. One study in 2004 found that among those who reported knowing someone who is gay, 65% favored either gay marriage or civil unions, while only 35% of those who reported not knowing any gay people supported them.

A second reason that gay marriage seems inevitable is that young people so strongly support it. One study by political scientists found a gap of 44 percentage points between the oldest and youngest survey respondents in their attitudes toward gay marriage. A 2011 poll found that 70% of those age 18 to 34 supported gay marriage. It is hard to imagine a scenario in which young people’s support for gay marriage dissipates as they grow older.

The trend in favor of gay marriage has accelerated dramatically in the last three years. Before 2009, the annual rate of increase in support for gay marriage was about 1.5 percentage points, but since then it has been closer to 4 percentage points. Statistical models predict that in another dozen years, every state will have a majority in favor of gay marriage.


In recent years, many conservatives have begun to acknowledge the inevitability of gay marriage, even as they continue to strongly oppose it. In March 2011, Albert Mohler, president of the Southern Baptist Theological Seminary, said on a Christian radio program that “it is clear that something like same-sex marriage … is going to become normalized, legalized and recognized in the culture.”

“It’s time,” he continued, “for Christians to start thinking about how we’re going to deal with that.”

That a particular social change may be inevitable, given certain background conditions, does not mean that opponents will cease fighting it. White Southerners continued to massively resist Brown long after most of them came to believe that school desegregation was inevitable.

Similarly, those who believe that gay marriage contravenes God’s will are not likely to stop fighting it simply because their prospects of success are diminishing. Moreover, because religious conservatives are both intensely opposed to gay marriage and highly mobilized politically, they are likely for the next several years to continue exerting significant influence over Republican politicians who need their support to win primary elections.


Although the ultimate outcome of the contest over gay marriage no longer seems in doubt, plenty of fighting remains until that battle is over.

Michael J. Klarman is a professor at Harvard Law School and the author of “Same-Sex Marriage Litigation and Political Backlash,” to be published this fall.