Current generative theory permits some grammatical constructions to play a dual role within syntactic theory, allowing them to serve both as data which must be explained and as arguments for the theory itself. This book argues that these roles can come into conflict and that the meta-theoretic (argument) role played by dual-role constructions circumscribes the data role played by the constructions. Such constructions become "imprisoned" by the theory because they cannot be re-analyzed in ways which would call the theory into question. Constraining the data to protect the theory, however, has obvious deleterious effects for the theory. In this book, the author looks at five constructions which play dual roles in generative (especially, minimalist) theory: antecedent contained deletion constructions, multiple-wh constructions, expletive constructions, do so constructions, and argument demotion constructions. The author shows that each of these constructions needs to be re-analyzed in ways which erode the argument role played by the construction in syntactic theory. The ultimate goal of this book, then, is to raise serious questions about current approaches to syntactic argumentation and to call for non-dual role syntactic analysis.