CRS Report on Presidential Claims of Executive Privilege

From the summary of Presidential Claims of Executive Privilege: History, Law, Practice, and Recent Developments (Aug. 21, 2012, R42670):

Presidential claims of a right to preserve the confidentiality of information and documents in the face of legislative demands have figured prominently, though intermittently, in executive congressional relations since at least 1792. Few such interbranch disputes over access to information have reached the courts for substantive resolution. The vast majority of these disputes are resolved through political negotiation and accommodation. In fact, it was not until the Watergate-related lawsuits in the 1970’s seeking access to President Nixon’s tapes that the existence of a presidential confidentiality privilege was judicially established as a necessary derivative of the President’s status in our constitutional scheme of separated powers.

[JH]