Speaking to hundreds gathered at the City County Building, Anderson called the war and other actions by the Bush Administration a "blight on our nation's honor" that can only be remedied by impeachment.
"We urge Congress to be silent no more and stop this war now," Anderson said.
About 500 people gathered at Pioneer Park and marched to the City County Building, led by six men carrying a mock coffin draped in an American flag. Chants of "War no more" were heard as the protesters arrived at the City County Building.
The protestors used the four-year anniversary of the invasion to speak out against Bush's plan to send 21,500 additional U.S. troops to Iraq and call for an end to the war, coinciding with rallies across the nation.
"We have already lost this war," said Robert Littlehale, a Vietnam War veteran and a member of Veterans for Peace, addressing a cheering crowd. Pointing to recent reports of patient neglect and "shabby treatment" at the Walter Reed Medical Center, Littlehale said veterans deserve better.
"We have to get out of this war," he said. "I am just disgusted." Carolyn Erickson, 60, was holding a sign with a picture of a woman veteran with both legs amputated below the knees, and the slogan "physical therapist for peace." "It's just a shame," said Erickson, who remembers aiding Vietnam War veterans in their recovery from injuries. "I hope it ends soon," she said. "I hope our politicians are courageous enough to come up with something to stop this."