Powell, who is doing a series of television interviews to promote a new book, endorsed Obama in the 2008 election but hasn't said who he'll back this year.
Like Obama, Powell spoke of personal connections in forming his opinion about same-sex couples getting married.
"But, as I've thought about gay marriage, I know a lot of friends who are individually gay but are in partnerships with loved ones," the retired Army general said. "And they are as stable a family as my family is. And they raise children. And so I don't see any reason not to say that they should be able to get married."
In 2010, Powell, who served as secretary of state under President George W. Bush, reversed his position on the military's "don't ask, don't tell" policy, saying he supported its repeal. He had opposed gays and lesbians serving openly in the military when he was chairman of the Joint Chiefs of Staff in the 1990s.
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