by Ryan P. Burge, Eastern Illinois University

I don’t think people can fully comprehend how unique an issue gay marriage is when it comes to public opinion research. Most political scientists study issues that may shift a few percentage points across a decade. By and large, change in public opinion is downright glacial. Gay marriage is not that way.

In November of 2005, Texans voted on Proposition 2 which amended the state code to define marriage between one man and one woman. 76.25% of voters approved of this change. Then, less than a decade later, the United States Supreme Court declared that gay marriage would be the law of the land. When the Court handed down that ruling, there was no widespread civil disobedience or demonstrations against the change. In fact, for almost all Americans, it’s an issue that has receded from public consciousness. Now, Mayor Pete Buttigieg is a front runner in the Democratic primary and is openly gay, when the prior Democrat occupant of the White House took office publicly stating that people like Pete shouldn’t have the right to get married.

Things have shifted quickly.

Before we get too far into the question of where the biggest shifts in opinion came from, I wanted to visualize just how much of an outlier same sex marriage is compared to other culture war issues. I grabbed two others – willingness to make pornography illegal and allowing a woman to obtain an abortion for any reason – to give a sense of how the American public looks on other topics related to morality and public policy.

In 1973, the GSS asked its first question about pornography, when 46% of all respondents believed that it should be made completely illegal, not just to young people, but to everyone. Over the last 45 years, the total decline in support for prohibiting pornograhy has been thirteen percentage points. When it comes to abortion, 36% of Americans were in favor of abortion on demand in the mid-1970’s. Now, that has risen to just about 50% of the population in 2018. In both cases, the shift across the time series has been less than fifteen percentage points.

Enter same sex marriage. The first time the GSS asked the question was in 1988, when just 12.4% of Americans said that they were in favor. For inexplicable reasons, the GSS didn’t ask the question again until 2004. But when they did support had jumped to 29.6%. That’s seventeen percentage points in sixteen years. That’s a larger shift than we’ve seen on the other two issues already. From there it’s just a steady upward trajectory. Support was 46.4% in 2010, and then jumped a full ten percentage points to 56.5% in 2014. From there, approval went up another ten percentage points by 2018. Now support is exactly two thirds of the population. Fully one fifth of Americans who believedgay marriage should not be allowed in 2010 changed their opinion by 2018.

I wanted to figure out where those shifts emerged from. Was it the religiously unaffiliated who led the way? Or was it mainline Protestants? I was also interested to see if the dramatic changes originated with the youngest Americans, or was it because of the baby boomers rethinking their position?

To do that I specified a simple logit model with the dependent variable being support for same sex marriage. I interacted four religious traditions: evangelicals, mainline Protestants, Catholics, and the nones with an age variable. I also included some basic controls for education, gender, and church attendance. I then ran the model for every year that the same sex marriage question was asked in the GSS.

In 1988, there’s not much to see – support is low for all traditions and all age groups. However, some changes begin to appear by 2004. Now, we can begin to see that the acceptance of same-sex marriage started to inch up among the youngest Americans in all traditions except for evangelical Christianity. As time passes, those lines become even steeper in their slope, which means that in each successive wave of the GSS, those under the age of 35 were becoming rapidly more accepting of same sex marriage. Because these surveys were only taken two years apart that means that the 18-35 year olds are largely the same across several waves. This isn’t the result of people aging into the GSS and shifting the percentages, it’s much more a result of people in their late teens and twenties just changing their minds.

But there’s one little quirk of the findings that’s worth discussing. Notice in the 2004 wave that the teal line (which represents the unaffiliated) is pointed pretty sharply downward. That’s because while nearly half of the youngest nones were in favor of gay marriage, support among those 65 and older was just 15%. That shifted significantly in just two years. By 2006, support among the youngest nones had edged up slightly, but support among the oldest religiously unaffiliated had jumped nearly twenty percentage points. That may be a backlash from the ten states that passed same-sex marriage amendments in the 2004 elections.

From this point forward, the youngest respondents continue to grow more supportive in each successive wave, while older individuals see support stall out around 35-40%. But between 2012 and 2014 another big shift happens, when support among Catholics, mainline Protestants, and the nones jumps to about fifty percent among those 65 and older.

This analysis seems to indicate that progress was incremental among the youngest, but was a punctuated equilibrium among the oldest respondents to the GSS.

Clearly, evangelicals are the outlier here. Beginning in 2004, the blue line is consistently lower at all points from the other three traditions. However, it’s worth pointing out that the line still has that downward tilt from left to right, meaning that younger evangelicals were becoming more supportive of gay marriage as time passed. In fact, since 2014 half of the youngest evangelicals in the sample believe that gay people should have the right to get married. In 2018, nearly 65% of evangelicals between 18 and 35 support same sex marriage, and support i’s up to one in three of the oldest evangelicals. That’s essentially a doubling in support in six years, which is staggering because the partisanship of young white evangelicals has not shifted at all.

If I were to describe how the shift happened on same sex marriage it would be gradually among some, but also all at once among others. It’s clearly an issue that evolved in an entirely different way from other issues as captured in survey data. Why? Well, I’m partial to the contact hypothesis. Succinctly stated, those who have positive contact with members of a minority group feel more warmly toward that group. In this case, as it has become more socially acceptable to be LGBT and more people felt comfortable to come out, which means that lots of Americans suddenly found themselves with a relative or close friend who was personally impacted by prohibitions against same sex marriage. It became a personal issue for many, and when that happened, opinions began to shift.

I think it’s fair to say that the culture war surrounding gay marriage is essentially over. Consider Kim Davis, a county clerk in Kentucky who refused to issue marriage licenses to same sex couples. When it became national news, very few rose up in her defense. Even Republicans running in the presidential primary refused to support her. Donald Trump said, “the decision’s been made, and that’s the law of the land.” She also found no support among Jeb Bush, Carly Fiorina, or Lindsey Graham. She served five days in jail for contempt (Mike Huckabee offered to go in her place) and then was defeated in the county clerk’s election in 2018. Since her electoral defeat, she’s almost completely retreated from public life, along with the issue that gave her fifteen minutes of fame.

It’s fair to say that we may never see another issue move so quickly, across so many parts of American society, as same sex marriage. A centerpiece of the culture war now seems like a fight from a bygone era. And, while support began to emerge among the young, it quickly spread to even the oldest American Christians. If people believe that the population of the United States is loathe to change its mind, this is the clearest counterfactual that exists.

Ryan P. Burge teaches at Eastern Illinois University in Charleston, Illinois. He can be contacted via Twitter or his personal website.  The syntax for this post can be found here.