The conflicts in Iraq and Afghanistan have generated intense interest in counterinsurgency within the U.S. armed forces, the intelligence community, the State Department, and the Department of Defense. However, subversion -- a critical part of the repertoire of many insurgent groups -- remains a neglected subject. This paper presents a set of case studies to explore the elements of subversion in-depth. It discusses preliminary ideas for combating subversive activities in the context of the ₃long war₄ against violent Islamist extremism and concludes with a discussion of how American support for countersubversion within authoritarian regimes can conflict with other important U.S. foreign policy objectives, such as the promotion of human rights.