I’m not sure whether or not Bush’s current claim of “Executive Privilege” will reach the courts. Truth is, only time will tell, but before we all begin to argue about whether or not Bush ‘has’ a right to Executive Privilege in “this” particular instance or the Congress has a right of oversight, I thought I’d present some background.
There seems to be three issues at play currently. The doctrine of “Executive Privilege”, the doctrine of “Congressional Oversight” and the doctrine of “Separation of Powers”. All three are implied in the Constitution but not explicitly expressed. Which, I’ll be honest, I found very interesting. I would have bet a paycheck that “Separation of Powers” was expressly stated. It isn’t. It is implied and the courts have of course held that it is true, but it is not expressly stated.
"The assertion is based on the constitutional doctrine of separation of powers, is always controversial, subject to interpretation, and often litigated."
Doctrine of Separation of powers
The first article of the Constitution says "ALL legislative powers...shall be vested in a Congress." The second article vests "the executive power...in a President." The third article places the "judicial power of the United States in one Supreme Court" and "in such inferior Courts as the Congress...may establish."
I couldn’t find a good reference on “Congressional Oversight”, but I did read something and I’ll try to paraphrase it. [Sorry for the lack of a link]. Just like Executive Privilege and Separation of powers, Congressional Oversight is not expressly stated in the Constitution. It is implied though because of the Power of Impeachment. In order to impeach any Executive Branch member, Congress would have to investigate. The oversight power is implied in the power to impeach.
From the case law and examples I read, none of these powers is absolute, which makes separation not absolute, executive privilege is not absolute and congressional oversight is not absolute. I think the Framers intended that each situation would speak for itself. Which to be honest is better for all of us.
And that seems to be the overriding principle to all of this. While the Constitution does not set up the most efficient government, it is the form of government that affords us [the citizens] the most freedom. No branch is immune from the other [depending on the circumstances] and no branch is at the mercy of the other either.
Case law seems to side on the principle of “overriding public interest” more than anything. When there “was” an overriding public interest, the public was served. When there wasn’t, the Branch retained its separation. Which on its face seems fair.
The following is some historical decisions and cases. [all emphasis added parts are mine]
For example, in 1796, President Washington refused to comply with a request by the House of Representatives for documents relating to the negotiation of the then-recently adopted Jay Treaty with England. The Senate alone plays a role in the ratification of treaties, Washington reasoned, and therefore the House had no legitimate claim to the material. Accordingly, Washington provided the documents to the Senate but not the House.
Eleven years later, the issue of executive privilege arose in court. Counsel for Aaron Burr, on trial for treason, asked the court to issue a subpoena duces tecum--an order requiring the production of documents and other tangible items--against President Thomas Jefferson, who, it was thought, had in his possession a letter exonerating Burr.
After hearing several days of argument on the issue, Chief Justice John Marshall issued the order commanding Jefferson to produce the letter. Marshall observed that the Sixth Amendment right of an accused to compulsory process contains no exception for the President, nor could such an exception be found in the law of evidence. In response to the government's suggestion that disclosure of the letter would endanger public safety, Marshall concluded that, if true, this claim could furnish a reason for withholding it, but that the court, rather than the Executive Branch alone, was entitled to make the public safety determination after examining the letter.
Jefferson complied with Marshall's order. However, Jefferson continued to deny the authority of the court to issue it, insisting that his compliance was voluntary. And that pattern persists to the present. Thus, President Clinton negotiated the terms under which he appeared before Independent Counsel Kenneth Starr's grand jury, rather than simply answering a subpoena directing him to appear.
US Vs. Nixon 
…. ...Notwithstanding the deference each branch must accord the others, the "judicial Power of the United States" vested in the federal courts by [the Constitution] can no more be shared with the Executive Branch than the Chief Executive for example, can share with the Judiciary the veto power, or the Congress share with the Judiciary the power to override a Presidential veto. Any other conclusion would be contrary to the basic concept of separation of powers and the checks and balances that flow from the scheme of a tripartite government. We therefore reaffirm that it is the province and the duty of this Court "to say what the law is" with respect to the claim of privilege presented in this case.
The second ground asserted to support 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 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. The President's need for complete candor and objectivity from advisers calls for great deference from the court. However, when the privilege depends solely on the broad, undifferentiated claim of public interest in the confidentiality of such conversations, a confrontation with other values arises. Absent a claim of need to protect military, diplomatic, or sensitive national security secrets, we find it difficult to accept the argument that even the very important interest in confidentiality of Presidential communications is significantly diminished by production of such material for in camera inspection with all the protection that a district court will be obliged to provide.
News Hour: March 24, 1998
KATHLEEN SULLIVAN, Stanford University Law School: Well, Margaret, it's true, it's not in the words of the Constitution, but it comes from the principle in the Constitution that we have the separation of powers. The White House can't be made subject to the Congress or to the courts by having inquiries that would make it unable--make the President unable to meet with his top advisers. It really reflects the very common sense principle that you couldn't conduct policy-making in the White House if every top aide to the President knew that his or her communications with the President or with each other could be revealed to the whole world at the drop of a hat. Nobody could make policy under that kind of circumstance.
So for a quarter of a century the Supreme Court has said that when the President or the President's top aides communicate with one another about matters of national policy, they are presumptively privileged in those communications and a prosecutor can't get hold of those communications unless that prosecutor can show not only that he might find something relevant in them but that he has some very specific piece of evidence that is very important, that is in those communications, and--and this is crucial--which he cannot find elsewhere through due diligence. That's the showing that Kenneth Starr would have to make to overcome the showing of executive privilege in this case. Now, as to arguments that it's not properly raised, of course, it's properly raised any time there is a matter of national policy that's being discussed by the President or by his top aides.
MARGARET WARNER: Douglas Kmiec, do you agree with that analysis?
DOUGLAS KMIEC, Notre Dame University Law School: I think Professor Sullivan has well stated the nature of the privilege. But I think we fundamentally disagree perhaps on whether or not there's any matter of national policy here. It's longstanding practice--and it certainly was by memorandum within the Reagan administration--that executive privilege should only be asserted under--and these are the words of the memorandum--the most compelling of circumstances, when it relates, as Kathleen said, to national policy.
CHENEY, V.P. PRESIDENT OF U.S. Vs. UNITED STATES DISTRICT COURT FOR THE DISTRICT OF COLUMBIA et al.
So, what did I learn?
I learned some things “I thought” were explicit in the Constitution—aren’t. The implied powers aren’t absolute.
I learned that the branches are separate, but not absolutely separate if there is a public interest. That this weird doctrine provides that no one branch can grab power and that no one branch can intrude on the other either. A very strange balancing act all in all.
I learned that all of these doctrines are valid, and that each side is actually right as far as it goes. Congress can use its power of oversight. The President can refuse claiming Executive Privilege, and it could end up in Court because the Court decides what the law really means. Each side can argue its case. It’s not a question of absolute right or wrong.
More importantly., I learned that the “People” hold the key to the answers to these questions usually.
Is there an overriding public interest to know?