In support of his claim of absolute privilege, the President's counsel urges two grounds, one of which is common to all governments and one of which is peculiar to our system of separation of powers. The first ground is the valid need for protection of communications between high Government officials and those who advise and assist them in the performance of their manifold duties; the importance of this confidentiality is too plain to require further discussion. Human experience teaches that those who expect public dissemination of their remarks may well temper candor with a concern for appearances and for their own interests to the detriment of the decisionmaking process. [Footnote 15] Whatever the nature of the privilege of confidentiality of Presidential communications in the exercise of Art. II powers, the privilege can be said to derive from the supremacy of each branch within its own assigned area of constitutional duties. Certain powers and privileges flow from the nature of enumerated powers; [Footnote 16] the protection of the confidentiality of
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Presidential communications has similar constitutional underpinnings.
The second ground asserted by the President's counsel in support of the claim of absolute privilege rests on the doctrine of separation of powers. Here it is argued that the independence of the Executive Branch within its own sphere, Humphrey's Executor v. United States, 295 U. S. 602, 295 U. S. 629-630 (1935); Kilbourn v. Thompson, 103 U. S. 168, 103 U. S. 190-191 (1881), insulates a President from a judicial subpoena in an ongoing criminal prosecution, and thereby protects confidential Presidential communications.
However, neither the doctrine of separation of powers nor the need for confidentiality of high-level communications, without more, can sustain an absolute, unqualified Presidential privilege of immunity from judicial process under all circumstances.