That there is a social problem presented by obscenity is attested by the expression of the legislatures of the forty-eight States, as well as the Congress. To recognize the existence of a problem, however, does not require that we sustain any and all measures adopted to meet that problem. The history of the application of laws designed to suppress the obscene demonstrates convincingly that the power of government can be invoked under them against great art or literature, scientific treatises, or works exciting social controversy. Mistakes of the past prove that there is a strong countervailing interest to be considered in the freedoms guaranteed by the First and Fourteenth Amendments.