Thinking about the seemingly rapid advances the once-toxic cause of marriage equality is making in public opinion polls illustrates, I think, the fact that not only do politicians take cues from public opinion, but the public takes cues from politicians.
In this particular case, it’s been clear for a few years now that the trend in public opinion was ineradicably moving in the direction of equality. That’s encouraged a lot of the more far-sighted political elites to start moving in a more gay-friendly position. You see this especially among conservatives where for the past few years supporting civil unions or full marriage equality has been the method of choice for demonstrating reasonableness. And I think that elites shifting to more gay-friendly positions has a substantial impact on the large number of Americans who I think are basically fair-minded but who, being of a certain age, just found the idea of same-sex marriage initially too shocking to contemplate.
Meanwhile, as more and more jurisdictions have permitted marriage or civil unions, the sky keeps not falling. And all that only further accelerates the trend.