Transcript for ARCHIVAL VIDEO: President Obama Announces His Support for Same Sex Marriage in 2012
Hours ago President Obama speaking exclusively to ABC's Robin Roberts and announcing something no US president has ever said. That he supports same sex marriage for years he only endorsed civil unions claiming his position on the polarizing question of marriage was still quote evolving. Then last weekend Vice President Biden surprised everyone by seeming to endorse gay marriage and today the president himself. Told Robin how and why his own thinking has changed. Mr. President are you still opposed to same sex marriage I've always been adamant that. Gay and lesbian. Americans should be treated fair and equal and I was sensitive to the fact that. For a lot of people. The word marriage was something that. Evokes very powerful traditions religious beliefs and soul. But I have to tell you that over the course of several years as I've talked. Friends and family. And neighbors when I think about. Members of my own staff wore an incredibly committed monogamous relationship same sex relationships. For raising kids together. When I think about. Those soldiers or airmen or Marines are. Sailors who were out there fighting on my behalf. And yet feel constrained. Even now the Don't Ask Don't Tell is gone because. They're not able to. Commit themselves in a marriage. At a certain point I've just concluded that. For me personally. It is important for me to go ahead and a firm. That. I think same sex couples should be able to get where. In its interest and some of this is also generational. You know Malia and Sasha they've got friends whose parents are. Same sex couples the other been times where Michelle and I have been some around the dinner table we have taught them. About their friends and their parents and Malia and Sasha would it when dawn on them but somehow. Their friends' parents. Would be treated differently it doesn't make sense than a minute and frankly. That's the kind of thing but pulse. A change of perspective did you discuss this with mrs. Obama the same sex marriage. Issue what I did something none of this is something that we are we've talked about. You know over the years and she feels the same way that I. And that is that in the end. That the values that. I care most deeply about she cares most people is. Is how we treat others who were both. Practicing Christians and and obviously. This position may be considered put us at odds with the views Brothers but you know when we think about our faith. The thing. You know at at route that we think about is not only. Christ's sacrifice himself on our behalf. But it's also the golden. Treat others the way you won't be true. About Vice President Biden never did presumed that Vice President Biden had forced the president hand and you talk about. I'd ask him about that and then the president had a big smile on his face when I product Joseph Biden's name and said that it was an authentic response. By the vice president when he said he was absolutely comfortable is absolutely comparable with same sex marriage and the president indicated that this was a discussion that they happen having. And that they would've had. Perhaps prior to the election and the vice president may have had this to hand and jumping the gun just. Ahead that everyone says Biden will be Biden right these are president said that himself. Right Robin well as we've said this is a historic cultural and political event in this country. And head on back to New York great interview thanks thing.
This transcript has been automatically generated and may not be 100% accurate.