This document discusses the economic rationale for government intervention in markets. It outlines several types of market failures like public goods, externalities, and natural monopolies that can lead to inefficient market outcomes. The document argues that in the presence of market failures, governments have an allocative role to play in correcting these inefficiencies. It also discusses other roles of governments, including stabilization of the economy and regulation to ensure orderly private exchanges. The document provides examples of how governments pursue allocative objectives in areas like water supplies and broadcasting spectrum. Finally, it briefly touches on the distributive and regulatory roles of governments.