Representatives of almost a dozen civic and anti-war groups announced their plans at a news conference Tuesday in Washington. Organizers say they expect tens of thousands of people to join the .
Anti-war activist Cindy Sheehan says the protesters are sending a message to Congress to stop the war. "We have to stand up and say, 'You know what? We went out in record numbers on November 7th [election day] and we voted against George Bush. We voted against his lies, we voted against his war, we voted against further aggression and we voted for you to stop it?."
Sheehan's son was killed in Iraq three years ago. She has been one of the most prominent American anti-war activists since 2005, when she staged a vigil outside President Bush's Texas ranch.
The march on the Pentagon this month will come 40 years after a similar mass protest in 1967, a watershed event in the anti-Vietnam War movement.