In The Uses of Argument (1958), Stephen Toulmin proposed a new, dialectically grounded structure for the layout of arguments, replacing the old terminology of “premiss” and “conclusion” with a new set of terms: claim, data (later “grounds”), warrant, modal qualifier, rebuttal, backing. Toulmin’s scheme has been widely adopted in the discipline of speech communication, especially in the United States. In this paper I focus on one component of the scheme, the concept of a warrant. I argue that those who have adopted Toulmin’s scheme have often distorted the concept of warrant in a way which destroys what is distinctive and worthwhile about it. And I respond to criticisms of the concept by van Eemeren et al. (The study of argumentation. Irvington, New York, 1984), Johnson (The rise of informal logic, pp. 116–152, Newport News, Vale Press 1996) and Freeman (Dialectics and the macrostructure of arguments: A theory of argument structure. Foris, Berlin, 1991). Their criticisms show the need for some revision of Toulmin’s position, but his basic concept of warrant, I shall argue, should be retained as a central concept for the evaluation of arguments.