John has been a writer, researcher and organizer focused on demilitarization and human rights, especially in the United States and Latin America, for more than 35 years. He co-authored the "Care First, Jails Last” policy adopted by Alameda County, as well as local legislation on militarized equipment used by police in Oakland and Berkeley, California. He represented AFSC in the Stop Urban Shield Coalition to end a militarized SWAT team competition, including representing the coalition in two county committees that helped reformulate emergency response policies in Alameda County and ended Urban Shield. 

From 1989 to 2014, he served the interfaith pacifist organization Fellowship of Reconciliation (FOR), as coordinator of the Task Force on Latin America and the Caribbean, where he founded the FOR Colombia peace team. 

He is the author of Emperors in the Jungle: The Hidden History of the U.S. in Panama (2003) and Plan Colombia: U.S. Ally Atrocities and Community Activism (2018), both published by Duke University Press.

John has been quoted in the LA Times, the Washington Post, the Nation, and Counterpunch, among other outlets. He is also a blogger for the Huffington Post.