The thesis has closely examined that an important shortcoming of the Keynesian analysis is the neglect of potential tax-induced aggregate supply effects, and therefore, just as Marshall's proverbial scissors with one "misplaced" blade, the government cannot make proper policy decision. Hence, this paper incorporates the tax-induced aggregate supply effects into the analysis. When a model does not include the supply-side effects of tax-induced, it degrades to a Ramirez (1986) and cannot be sued for policy assignment. On the other hand, a model incorporates the tax-induced aggregate supply effects remedies the flaws in Ramirez (1986) and can be used for appropriate policy assignment.