Amid chants of “Arrest Bush,” hundreds of antiwar activists participated in a peaceful but boisterous sit-in outside the White House Monday, as part of a day of protests that saw Cindy Sheehan and others taken into custody.

Sheehan, the California woman whose 24-year-old son Casey was killed in the Iraq War, drew international attention in August when she camped out near George Bush’s ranchette in Crawford, Texas, as part of an effort to secure a face-to-face meeting with the President. Over the weekend, the woman whom Congressional Progressive Caucus co-chair Lynn Woolsey, D-California, praised for “waking up America” brought her demand to Washington, where she participated in the mass demonstration against the war on Saturday.

On Monday, more than 1,000 people gathered in Lafayette Park across from the White House. Code Pink activists stretched a huge “Mothers Say No to War” banner across Pennsylvania Avenue, and early in the afternoon several hundred members of the crowd, including Sheehan, approached the northwest entrance of the executive residence. Holding a picture of her son in his US Army uniform, Sheehan again requested an opportunity to talk with the President about the Iraq War.

After about ten minutes, Sheehan joined a large sit-in along the fence outside the White House. As the group chanted “Stop the War!” and “The whole world is watching!” she was the first arrested by US Park Police. Like the others who were taken into custody, she was charged with demonstrating without a permit, a misdemeanor that carries a $50 fine. (In addition to the 370 people who joined the sit-in near the White House, another forty-one–including a number of members of the group Veterans for Peace–were arrested earlier in the day near the Pentagon.)

Though Bush did not meet with Sheehan on Monday, his spokesman Scott McClellan was forced to acknowledge that the President is “very much aware of the people here who have come to Washington.”

McClellan, whose statements often display all the authenticity of pronouncements from the Politburo, made a hamhanded attempt to compare the weekend’s mass anti-war protests with the tiny counter-protests by groups that are supportive of the war–suggesting that the crowds that poured into Washington included “some [who had come] to express support for the steps that we’re taking and a number of others that have expressed a different view.”

McClellan did allow as how the antiwar activists were “well-intentioned.” But he added, “The President strongly believes that withdrawing [US troops from Iraq] would make us less safe and make the world more dangerous.”

Sheehan took a different view, suggesting that the real danger comes from those in Congress who gave the Bush Administration permission to launch its war, and who have failed to demand an end to the misguided mission.

“We need a people’s movement to end this war,” Sheehan told Saturday’s rally, during which she urged activists to increase the pressure on members of Congress to break with Bush and support the withdrawal of US forces from Iraq. “We’re going to ask them: How many more of other people’s children are you willing to sacrifice for the lies?”

The White House may not be taking Sheehan or the broader antiwar movement seriously, but some members of the House of Representative seem to be getting the message. Woolsey, who has sponsored a resolution calling for an exit strategy, told Saturday’s rally of antiwar activists: “You are far ahead of the Congress and the policy-makers on this war.”