Once the government can demand of a publisher the names of the purchasers of his publication, the free press as we know it disappears. Then the spectre of a government agent will look over the shoulder of everyone who reads. ... Fear of criticism goes with every person into the bookstall. The subtle, imponderable pressures of the orthodox lay hold. Some will fear to read what is unpopular, what the powers-that-be dislike. ... fear will take the place of freedom in the libraries, book stores, and homes in the land.

It is better, so the Fourth Amendment teaches us, that the guilty sometimes go free than the citizens be subject to easy arrest.

We do not sit as a super-legislature to weigh the wisdom of legislation.

The first opinion the Court ever filed has a dissenting opinion. Dissent is a tradition of this Court... When someone is writing for the Court, he hopes to get eight others to agree with him, so many of the majority opinions are rather stultified.

Common sense often makes a good law.

Sunlight is the best disinfectant.

Security can only be achieved through constant change, through discarding old ideas that have outlived their usefulness and adapting others to current facts.