WASHINGTON - Liam Madden opposed the war in Iraq even before he deployed with his Marine unit in late 2004. But he came home convinced more than ever that the war is wrong.

"The more informed I got, the more I opposed the war," said Madden, 22, a Marine Corps sergeant in Quantico, Va. "The more people who died there, the longer we stayed there, the more I opposed the war. The more I know, the easier it is to support withdrawal."

Madden is one of about 118 members of the U.S. military who plan to petition Congress asking that U.S. forces be withdrawn from Iraq and brought home, attorney J.E. McNeil said. McNeil is advising the grass-roots group of active-duty service members, who organized the petition drive through a Web site ( www. appealforredress.org ).

In a rare display of public dissent, Madden and another serviceman plan to go public today with their disapproval. Members of the military are more limited than civilians are in how they can express dissent.

Although a number of troops, including at least one officer, have been brought up on charges for refusing to serve in Iraq, and dozens more have deserted, this is the first time that serving members of the U.S. military have publicly petitioned Congress to end the war.

The grass-roots movement of active-duty service members is based in Norfolk, Va., and is sponsored by several anti-war groups, including Iraq Veterans Against the War, Veterans for Peace, and Military Families Speak Out.

Under military regulations, troops are free to speak their minds as long as they're not on duty, not in uniform and aren't saying anything that is disrespectful to their chain of command or the president, McNeil said.

The Military Whistleblower Protection Act of 1995 allows servicemen and women to communicate grievances directly to Congress.