"The Defense of Marriage Act was a very successful piece of legislation. Not only did it create two categories of marital benefits -- one for straights, and one for gays -- but it had a profound silencing effect on political leaders. Between 1996 -- when DOMA was passed -- and 2006, only one member of the U.S. Senate came out in support of same-sex marriage, according to data collected by Wonkblog's Dylan Matthews: Dean Barkley of Minnesota, who replaced Paul Wellstone after his death in 2002 and served a grand total of 61 days in office. But starting in 2012, that began to shift -- thanks in large measure to Joe Biden. The vice president got the ball rolling on the new round of gay-marriage pronouncements on May 6. "I am absolutely comfortable with the fact that men marrying men, women marrying women and heterosexual -- men and women marrying -- are entitled to the same exact rights, all the civil rights, all the civil liberties," he told NBC's Meet the Press. That put pressure on Obama to make his own views clearer -- not that there was much doubt about what they were. "There's no doubt in my mind that the president shares these values and that's why it's time for him to speak out in favor of marriage equality as well," Joe Solmonese, president of the Human Rights Campaign, said in a statement. Days later, Obama sat down with ABC's Robin Roberts, telling her, '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.""