Abuses and failures are enabled through excessive over-classification -- see "WikiLeaks and 9-11: What If?", through the use of "State Secrets" privilege to keep cases out of the courts and through lack of government whistleblower protection.
The English historian Lord Acton, who figured out that power corrupts, also realized that, "Everything secret degenerates, even the administration of justice; nothing is safe that does not show how it can bear discussion and publicity."
(Note: You can view every article as one long page if you sign up as an Advocate Member, or higher).