NEW YORK -- Actress Susan Sarandon, a longtime liberal political activist and outspoken opponent of the Iraq war, endorsed an anti-war Democrat challenging Sen. Hillary Rodham Clinton's re-election bid Tuesday.

Sarandon is backing Jonathan Tasini, a labor advocate and former president of the National Writers' Union, who has based his longshot campaign on Clinton's vote in 2002 authorizing military intervention in Iraq.

Clinton, who is widely considered the front-runner for the 2008 Democratic presidential nomination if she chooses to run, has sharply criticized the Bush Administration's handling of the war. But she has also refused to call for American troops to be removed from Iraq.

Sarandon has been a harsh critic of Clinton's vote on the war, telling a British television interviewer last month that Clinton had "crumbled under the pressure of the moment." She also told ITV1 that she wasn't enthusiastic
about a Clinton presidential candidacy.

Announcing Sarandon's endorsement, Tasini called the 59-year old Academy Award winner a "passionate advocate for human rights, justice and civil liberties" and said he was "honored" to have her support.

"She has never wavered when the call has come for people to stand on the front lines in support of progressive principles that affect the lives of so many people in our country," Tasini said.

Sarandon did not offer a statement of her own but an aide confirmed she was backing Tasini.

Earlier this month, Sarandon joined Clinton at a rally in Washington for the Christopher Reeve Foundation, which promotes research on spinal cord injuries. There, Sarandon offered nothing but praise for Clinton, saying "we are all very lucky to have her here today as a leader in Congress."