The U.S. Army increasingly faces adversaries that are difficult to define. The threat landscape is further complicated by the silent partnership between criminal organizations, irregular groups, and nation-states. This collaboration, whatever its exact nature, is problematic, because it confounds understanding of the adversary, making existing countermeasures less effective, and thus directly challenging U.S. national security interests. Military action taken without full appreciation of the dynamics of the nature of these relationships is likely to be ineffective at best or suffer unintended consequences. This monograph provides a comprehensive assessment of the threat to U.S. national security interests posed by the silent partners, as well as how the vulnerabilities of the relationships could be exploited to the advantage of the U.S. Army.