Nate Silver, at Five Thirty Eight, has a new post up about the increasing support for same-sex marriage in the U.S. In the past few months, four polls Silver deems credible have found, for the first time, more than half of Americans supporting legalizing same-sex marriage. Here’s a graph Silver created showing the results of polls on the topic over time (an update of his earlier graph):

Of course, as Silver points out, results of public opinion polls don’t necessarily translate into immediate changes in politicians’ positions. Support for same-sex marriage is surely unevenly distributed, meaning some politicians will still find opposition to it to be a winning electoral strategy in their districts. Or they may count on the fact that many voters may support same-sex marriage but not view a candidate’s position on this issue as a deal-breaker. And, of course, sometimes politicians take a position and stick to it regardless of opinion polls.

That said, as with public opinion about gays and lesbians serving in the military, the trend line is clear, and it seems likely that fewer politicians will see opposition to same-sex marriage as a sure-fire winning strategy, as many have in the past.