The MemoryBlog points to a Washington Post article (hot tip: try the DailyKos newspaper logins) highlighting the danger (and absurdity) of the government's misuse of its ability to classify information. It examines the Department of Justice's use of "secret evidence" in the ACLU's cases against it:

Among the phrases originally redacted by the government was a quotation from a 1972 Supreme Court ruling: "The danger to political dissent is acute where the Government attempts to act under so vague a concept as the power to protect 'domestic security.' Given the difficulty of defining the domestic security interest, the danger of abuse in acting to protect that interest becomes apparent."

The ACLU has a web feature up about the issue.