The 9/11 attacks on the United States have motivated psychologists to advance counterterrorism and related operations through psychological principles and skills. These operational psychologists seek to legitimize adversarial interventions against targets by prioritizing societal welfare over traditional, individual-focused principles of psychological ethics. In this essay, we distinguish adversarial operational psychology, which facilitates deceptive and coercive operations, from collaborative operational psychology, which optimizes personnel performance in high-risk operations. Our analysis finds that adversarial operational psychology is largely unsupported by the American Psychological Association Ethics Code, that its potential benefits are exceeded by the likelihood of irreversible harms, and that its military necessity is undemonstrated. We offer a three-factor framework for distinguishing between adversarial and collaborative operational psychology, and we recommend institutional separation of these roles so that professional psychologists do not serve in adversarial capacities.