Why does the Justice Department’s secret subpoena of the phone records of Associated Press journalists matter so much? Try these words from the late constitutional scholar Alexander Bickel in “The Morality of Consent” (1975), as cited in a dissenting opinion in New York Times v. Gonzales:

Indispensable information comes in confidence from officeholders fearful of competitors, from informers operating at the edge of the law who are in danger of reprisal from criminal associates, from people afraid of the law and of government — sometimes rightly afraid, but as often from an excess of caution — and from men in all fields anxious not to incur censure for unorthodox or unpopular views . . . . Forcing reporters to divulge such confidences would dam the flow to the press, and through it to the people, of the most valuable sort of information: not the press release, not the handout, but the firsthand story based on the candid talk of a primary news source. . . . [T]he disclosure of reporters’ confidences will abort the gathering and analysis of news, and thus, of course, restrain its dissemination. The reporter’s access is the public’s access.