Anderson, also a vocal critic of the war in Iraq and of President Bush, spoke at a rally following the march and echoed the rally's main mantra, calling for the impeachment of the president and of Vice President Dick Cheney.
"Impeach these men who betrayed and harmed us all," Anderson said. "We are here to say, 'No more!"'
Anderson made almost identical remarks during a similar rally held in front of the U.S. Capitol in January, leading the crowd in a chant of "No More!" as he listed various acts he and the crowd of thousands would like to see stopped.
"No more movement toward war in Iran. ... No more wars of aggression. ... No more violations of the United Nation's charter," Anderson said during Saturday's speech.
"We are not the kind of nation that tolerates the violation of treaties, wars of aggression and human rights abuses perpetrated by our vice president and our president," he said. "We have always been proud to distinguish ourselves from governments that ignore the rules of law, which violated treaties and their own constitutions with impunity. Now, under the Bush administration, we are becoming like them."
The protest initiated by the Act Now to Stop War and End Racism Coalition, better known as the A.N.S.W.E.R. Coalition, and sponsored by 1,500 organizations marked the fourth anniversary of the Iraq invasion and the 40th anniversary of an October 1967 March on the Pentagon to protest the Vietnam War.
Other protests took place in cities across the nation. In Salt Lake City, a protest dubbed "The Liars Convention" was held on the sidewalk in front of the Wallace F. Bennett Federal Building. Like their counterparts in Washington, the Utah protesters took aim at the Bush administration, the military and the corporate media.
The Washington event was the first time Anderson and Sheehan had actually crossed paths. He invited her to participate in a rally last August, when Bush came to Salt Lake City to speak at the American Legion convention, but she was recovering from surgery.
Sheehan's son, Casey Sheehan, was killed in Iraq in April 2004, and she has since been protesting the war "to show that no citizen in this country is above the law," she said in an interview.
Sheehan said she knows Anderson is harshly criticized by some residents of Salt Lake City and Utah for his participation in such events.
"I think he is very courageous to stand up for his values and his beliefs," Sheehan said.
The march started in a muddy part of park land near the Lincoln Memorial and made its way over a bridge into Virginia to the cold asphalt in one of the Pentagon's massive parking lots.
"This is what democracy looks like!" a crowd of protesters yelled as the march began.
Counterprotesters war supporters, veterans, military members and others lined the sidewalk across the street from the marchers. U.S. Park Police, in full riot gear, were there to keep the two sides apart. While there were loud and sometimes colorful verbal exchanges between the two groups, there was no violence.
As the marchers carried signs calling for impeachment and an end to the war, the counterprotesters carried signs saying "Stand behind our president," "God bless the military," "Safe since 9-11" and "America: Home of the free because of the brave."
When the marchers crossed into Virginia, a band of counterprotesters stood outside Arlington National Cemetery with a banner saying "Go to hell traitors. You dishonor our dead on hallowed ground."
Bo Scott, 45, of Newport News, Va., rode with his chapter of the U.S. Military Vets Motorcycle Club to make sure no one defaced any of the monuments.
He called the anti-war protesters and those lining the street to support the war "a beautiful thing" something he has fought to protect.
"My tolerance of that stops when they start defacing monuments, though," said Scott, who goes by the nickname "Ghost." He also wanted the active military fighting overseas "to see that they have support."
Scott said the anti-Bush protesters have every right to call for Bush's impeachment but that he "wouldn't run around with a sign saying 'impeach Bush."'
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