Last month, Indiana governor Mike Pence took a quiet moment for an off-the-record signing of the relatively innocuous-sounding Religious Freedom Restoration Act. Within a few days, everyone from NASCAR to Nick Offerman had blasted the state, with Politico going as far as to suggest that Pence had torpedoed his chance for the White House by adopting a law without realizing it could be used to discriminate against people on the basis of sexual orientation. After it became a national embarrassment for his state, Pence had to scramble to clarify the law.

At that point, the intent of the RFRA didn't matter; it threatened to do what its critics said, and overwhelming pressure forced its change, and the extent of the pressure took people on both sides by surprise.

Behind that is some math. The General Social Survey, run for decades by NORC at the University of Chicago, has been keeping tabs on what its name suggests—what Americans think about stuff, generally stuff that's important on a national level. When a topic becomes high-profile enough for social scientists, journalists, and the general public to care what their countrymen think, NORC will often add a question about it.

In 1988, one of those questions was whether Americans supported same-sex marriage. Support hovered around ten percent; NORC didn't ask the question from 1990 to 2002.

When NORC reintroduced the question in 2004, support had risen to around 30 percent, but was still low in certain age groups: under 20 percent among the 65+ age group, under 30 percent for ages 35-64, and up to around 40 percent for 18-34. 

Today? 72 percent of those 18-34 support the right; 56 percent from 35-49; 50 percent from 50-64; and 42 percent of those 65 and older. All told, the most recent GSS found that, for the first time in its reports, a majority of Americans support same-sex marriage. In fact, it's 56 percent.

That includes 45 percent of Republicans. Perhaps the most surprising result of all: support among Republicans for same-sex marriage was 30 percent in 2012. In two years, support increased by half. It's really an astonishing finding.

Nor is it just a matter of gay marriage, specifically—there's also the belief that same-sex relations are wrong, but nothing the government should concern itself with:

Americans’ attitudes about sexual relations between members of the same sex are shifting, but remain highly polarized. Fewer people than ever say that sexual relations between members of the same sex are always wrong (40 percent), and more people than ever say such relations are not wrong at all (49 percent). This represents a nearly 40-point shift in attitudes since 1987 when 79 percent of Americans said same-sex relations are always wrong, and just 12 percent said they are not wrong at all.

The RFRA found itself on the wrong side of history. But it shouldn't be surprising—it's rare that history changes so rapidly. The 2012 GSS found that just 30 percent of Republicans supported the right to gay marriage, a cakewalk in a GOP-dominated legislature. While most might assume those numbers would erode, the results from the 2014 GSS—released the same month Pence signed the bill—could only have been expected by the most optimistic of civil-rights activists. The arc of the moral universe may be long, but as the end comes in sight, the bend can come with great suddenness.