MELISSA BLOCK, HOST:
At that fundraiser tonight, President Obama is sure to get enthusiastic applause for his announcement yesterday that he supports same-sex marriage. The president's shift in his public stance mirrors a rapid change nationwide. These days a plurality of Americans say same-sex marriage should be legal. And in the past decade or so, that support has ticked upward steadily, a steep rise for an issue that was, even in the mid-'90s, opposed by a broad majority.
So why have attitudes about same-sex marriage changed so quickly? For more, we turn to Nate Silver, who has followed the issue and the numbers on his New York Times blog, FiveThirtyEight. Nate, welcome back to the program.
NATE SILVER: Thank you.
BLOCK: And to illustrate this rapid shift, give us some numbers. Give us a sense of how quickly this has shifted and to what extent.
SILVER: About 50 percent of people support same-sex marriage rights, about 45 percent oppose. So it's still basically 50/50, but you can see probably the support side having a little bit of an edge now. That's a big shift from even a couple of years ago.
Basically every year for the past eight years, you had the number who support same-sex marriage increase by two or three points per year. And the number who oppose if, of course, would decline then by two or three points per year.
And so that adds up to quite a bit of a shift in support over the span of eight or 10 years.
BLOCK: White House officials yesterday were saying they've never seen such rapid movement in public opinion on a major social issue like this. Does that square with what you're finding in numbers on other issues, as well?
SILVER: Yeah. I mean, sometimes on economic issues or issues related to domestic policy where there are events that intervene and rapidly change opinion, about a war or something. But about social issues, I mean, if you look at the numbers on abortion they've been pretty much the same for decades. Maybe on gun rights, there's been some movement toward the pro-Second Amendment side, but not as rapidly as you see on gay rights issues or on gay marriage in particular.
It's quite unusual for social issues to move even by two or three points a year, which, as we've seen, adds up to something pretty significant over a decade or so.
BLOCK: When you look at these numbers on same-sex marriage and public opinion, attitudes are very, very much tied with age, right?
SILVER: That's right. So if you look at people over the age of 65 there hasn't been that much shift, and about two out of three still oppose gay marriage. Whereas people under the age of 30, about two out of three support it; maybe even 70 percent or so support it. And that's one reason why you seem to see some momentum is that as a 17-year-old who grows up watching "Glee" and "Modern Family" becomes 18, and is included in surveys and is able to vote, then he or she would count in the polls as a supporter of gay marriage.
You know, meanwhile someone who is no longer with us and may have opposed it, you see the replacement of people in the electorate with a younger generation.
BLOCK: There are a lot of things that go into public opinion on this question I think that can't be measured easily in polls. What do you think some of the cultural issues or cultural factors are that go into maybe what's motivating people to change their mind about same-sex marriage?
SILVER: Well, I think there are a couple things. And number one is just when gay people are more open in their communities, then people develop more positive associations with them. It becomes less abstract. It becomes - well, I know this guy at work who has a partner he's been with for a long time. Or I know my daughter, or my daughter's friend, or my friend who's lesbian. And that makes the issue - it changes the game a little bit.
(SOUNDBITE OF LAUGHTER)
BLOCK: This might be the Dick Cheney model, right, with a daughter who is openly gay?
SILVER: Well, sure. Remember, I mean, Dick Cheney - as partisan as this issue is, it's somewhat less so than some other issues. And it does seem like the shift in opinion goes one way. You don't have a lot of people who at one point were in support of gay marriage and then oppose it. It seems like people might start out opposing it. It is the kind of traditional religious value in this country.
And then, as they meet more positive examples of just gay people in their lives, or gay relationships - even when they see examples on TV and in movies - that I think can shift the numbers and shift people's attitudes quite a bit.
BLOCK: Nate Silver runs The New York Times blog FiveThirtyEight. Nate, thanks so much.
SILVER: Thank you. Transcript provided by NPR, Copyright National Public Radio.