The power to make certain conduct illegal is granted to Congress by virtue of the Necessary and Proper Clause of the Constitution (art. I, § 8, cl. 18). Congress has the power to define and punish crimes whenever it is necessary and proper to do so, in order to accomplish and safeguard the goals of government and of society in general. Congress has wide discretion in classifying crimes as felonies or misdemeanors, and it may revise the classification of crimes.