This paper outlines a non-exhaustive inventory of presumptive argument schemes that can be used by legislators to rationally argue for and against the legitimacy of legislative ends. The inventory has both a descriptive and normative dimension. The inventory is descriptive because it is partly based on the empirical observation of arguments actually used by legislators in a sample of lawmaking debates. However, the inventory is also normative because - as I shall argue in this paper - the schemes identified in the sample are presumptive arguments schemes. They are therefore schemes with a claim to rationality, provided that certain conditions are met. The schemes included in the inventory are: the scheme of instrumental argumentation, the scheme from unintended consequences, the scheme from values, the schemes from model and antimodel, and the schemes from social demand.