I shall not today attempt further to define the kinds of material but I know it when I see it.

May the state fence in the harmless mentally ill solely to save its citizens from exposure to those whose ways are different? One might as well ask if the state, to avoid public unease, could incarcerate all who are physically unattractive or socially eccentric.

The First Amendment guarantees liberty of human expression in order to preserve in our Nation what Mr. Justice Holmes called a "free trade in ideas." To that end, the Constitution protects more than just a man's freedom to say or write or publish what he wants. It secures as well the liberty of each man to decide for himself what he will read and to what he will listen. The Constitution guarantees, in short, a society of free choice.

For the Fourth Amendment protects people, not places. What a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection. But what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.

Censorship reflects a society's lack of confidence in itself. It is a hallmark of an authoritarian regime.

The right to defy an unconstitutional statute is basic in our scheme. Even when an ordinance requires a permit to make a speech, to deliver a sermon, to picket, to parade, or to assemble, it need not be honored when it's invalid on its face.

The Court today holds the Congress may say that some of the poor are too poor even to go bankrupt. I cannot agree.