Returning to Fort Hood, Texas, Cline became an anti-war activist, serving as a civilian organizer of active duty servicemen at one of the first GI Coffeehouses, the Oleo Strut, in Killeen, Texas and producing a one-sheet underground newspaper on politics and veterans issues called "Fatigue Press", which was distributed clandestinely on the military base. He explained, "I was sent down to Fort Hood and that's when I really got hooked up with the GI movement." He soon realized the base was training soldiers just back from Vietnam in riot control to go to the Democratic National Convention in Chicago in 1968. There were a lot of soldiers not happy about this, "we fought the Vietnamese, now they want you to fight Americans. A lot of people identified with the demonstrators on different levels." "We decided to organize a movement against it because there was a lot of opposition to the ideal of going to Chicago." He joined Vietnam Veterans Against the War in 1970, where he served as a coordinator and national director, and remained a member until his death. He died on September 14, 2007, at his home in Jersey City, New Jersey at the age of 60.