If the rule of law doesn't constrain the actions of government officials, then nothing will. Continuous revelations of serious government lawbreaking have led not to investigations or punishment but to retroactive immunity and concealment of the crimes. Judicial findings of illegal government behavior have led to Congressional action to protect the lawbreakers. The Detainee Treatment Act. The Military Commissions Act. The Protect America Act. The FISA Amendments Act. They're all rooted in the same premise: that our highest government leaders have the power to ignore our laws with impunity, and when they're caught, they should be immunized and protected, not punished.
http://www.salon.com/opinion/greenwald/2008/07/12/torture/index.html