For over a decade and a half, Miller has written about border and immigration issues between the United States and Mexico.

He is a contributing editor on the NACLA Report on the Americas’ blog "Border Wars", and his work has also appeared in such places as the New York Times,[1] The Nation, Guernica,[2] and Common Dreams.

Miller has worked for both Borderlinks in Arizona and Witness for Peace in Oaxaca, Mexico, researching and assisting in resolving immigration issues.

[4] His first book, Border Patrol Nation: Dispatches from the Front Lines of Homeland Security was published in 2014.

[5] His second book Storming the Wall: Climate Change, Migration, and Homeland Security was published in 2017 and covers the interrelated nature of human migration, climate change, corporate investment in border militarization, and sustainability and environmental justice movements.