Read full Report: Obama Gay Marriage

President Barack Obama declared his support for gay marriage Wednesday.

WASHINGTON -- In a nod to a dramatic shift in public opinion, Barack Obama on Wednesday became the first sitting president to announce his support for same-sex marriage.

In a sit-down interview with ABC's Robin Roberts, Obama completed what has been a markedly long and oft-mocked evolution on the matter.

"I've always been adamant that gay and lesbian Americans should be treated fairly," Obama told Roberts, in an interview that will air in full on ABC's "Good Morning America" Thursday.


"I have to tell you that over the course of several years as I have talked to friends and family and neighbors when I think about members of my own staff who are in incredibly committed monogamous relationships, same-sex relationships, who are raising kids together, when I think about those soldiers or airmen or marines or sailors who are out there fighting on my behalf and yet feel constrained, even now that Don't Ask Don't Tell is gone, because they are 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 affirm that I think same sex couples should be able to get married," he said.