On July 23, 2004, five marines, two soldiers, and one airman became the most unlikely of antiwar activists. Young and gung-ho when they first signed up to defend their country, they were sent to fight a war that left them confused, enraged, and haunted. Once they returned home, they became determined to put their disillusionment to use. So that sultry summer evening, they mounted the stage of Boston's historic Faneuil Hall and announced the launch...