http://www.slate.com/articles/news_and_politics/politics/2015/06/supreme_court_gay_marriage_decision_why_politicians_and_judges_moved_so.html

Over a remarkably brief period of time, same-sex civil marriage has gone from being a cause advanced by a small handful of activists to one that’s been embraced by 60 percent of Americans, including a majority of Republicans under the age of 30. As we contemplate the monumental Supreme Court decision establishing a constitutional right to same-sex marriage, it’s worth stopping to consider why support for same-sex marriage has grown so rapidly.