WASHINGTON (AP) - Missouri Sen. Claire McCaskill says she is supporting a super political action committee encouraging Hillary Rodham Clinton to run for president in 2016.
McCaskill is the first sitting member of Congress to endorse the group, called Ready for Hillary.
The organization does not have official ties to the former secretary of state but it's trying to lay the foundation for another Clinton campaign.
McCaskill was an early supporter of Barack Obama when he was running for president in 2008. She says it's important for supporters of Clinton to start early and build a "grassroots army from the ground up" to help the former first lady if she decides to run for president.
McCaskill was re-elected to her second term in the Senate in 2012.
The Democratic senator announced her support for gay marriage on her blog. She says churches should never be required to conduct marriages outside their religious beliefs, but she believes "government should not limit the right to marry based on who you love."
McCaskill's announcement comes the same week that the U.S. Supreme Court is to hear a challenge to California's gay-marriage ban.
Missouri voters approved a constitutional amendment in 2004 limiting marriage to a man and a woman.
As recently as last year's Senate campaign, McCaskill said she supported states' rights to decide gay marriage and had no quarrel with Missouri's vote.
President Barack Obama announced his support for gay marriage last year.