Former Secretary of State Hillary Rodham Clinton, pictured in a video frame grab provided by the Human Rights Campaign, announces her support for gay marriage, putting her in line with other potential Democratic presidential candidates on a social issue that rapidly is gaining public approval. (AP Photo/Human Rights Campaign)

Former Secretary of State Hillary Rodham Clinton, pictured in a video frame grab provided by the Human Rights Campaign, announces her support for gay marriage, putting her in line with other potential Democratic presidential candidates on a social issue that rapidly is gaining public approval. (AP Photo/Human Rights Campaign)