For the past 40 years during which dual allegiance (DA) has been studied, precious little has been discovered that expands on the insights of early writers about the topic. This paper reviews the methodological and conceptual basis of DA, both of which are found wanting. Legal and ethical issues concerned with applications of DA research are not addressed appropriately by current investigators. Ideas for ameliorating some of these problems are recommended. A framework for additional research on DA is proposed that offers a plan for dealing with a number of fundamental questions about the scientific standing of the concept.