The phrases "executive privilege" and "separation of powers" do not appear in the Constitution. Nevertheless, the Constitution clearly creates three distinct departments, and some sort of executive privilege may properly be deduced from this general tripartite structure.
But what sort? In the 1974 Nixon Tapes Case, the Supreme Court recognized that presidential conversations with executive staff are presumptively privileged, but then proclaimed that, unless national security were involved, this executive privilege must yield whenever courts had need for specific, material, and relevant evidence. This is a rather puny privilege. Anyone can resist a subpoena that is overbroad or irrelevant. When husbands speak with wives, clients with attorneys, patients with doctors, or penitents with priests, these conversations are all entitled to far more protection than the Nixon Court gave to Presidents speaking with staffers.
Cheney rightly worries that the Nixon case and later lower court opinions have eroded executive privilege. In a system of separated powers, each branch must have some internal space a separate house to deliberate free from the intermeddling of other branches. Senators must be free to talk candidly with colleagues and staff in cloakrooms; judges need similar freedom to converse with each other in judicial conferences and with clerks in closed chambers; jurors deliberate in secret; and for similar reasons Presidents need room for confidential conversations with staff.
Imagine that the President is considering appointing some rising political star to high office. Aides brief the president on potential objections to the appointment, reporting facts and rumors about the star, her family, and her inner circle. To do his job right, the president needs this candid advice and information, but is unlikely to get it if the conversation can easily be subpoenaed in a lawsuit designed to embarrass the Administration or the potential nominee. For this reason, Chief Justice John Marshall explicitly refused to force Attorney General Levi Lincoln to disclose confidential conversations with President Jefferson in the famous 1803 case, Marbury v. Madison. (The Nixon Court somehow overlooked this part of Marbury.) The principle that cabinet officers report directly to the President, rather than to Congress or the courts, draws additional support from a little-noticed part of the Constitution known as the Opinions Clause.
But Cheney's case raises special complications. He is neither the President nor a cabinet or subcabinet official wholly within the executive branch. Constitutionally, he is also an officer of the legislature indeed, the Senate's presiding officer. Enron officials at these meetings were themselves not governmental officers of any sort. Nor was the topic here some purely executive issue like an appointment or a prosecution or pardon; rather it was what legislation to propose to Congress. When Senate Minority Leader Trent Lott meets with lobbyists about their legislative wish lists, these meetings are not privileged, even if Lott is acting in political partnership with the President and will later report to him. Constitutionally, how are Cheney's conversations with Enron decisively different?
It's a stretch to think the Enron officials themselves can claim "executive privilege." If the company itself can be directly subpoenaed, why can't Cheney be likewise subpoenaed to provide the same information? When a client talks to her lawyers with others in the room, she generally is deemed to have waived attorney client privilege; so too when penitents speak to priests outside the confessional seal. By similar logic, executive privilege is waived, or at least weakened, when executive officials meet with outsiders.
Also, executive privilege is weakest when Congress itself seeks to pierce it. Private plaintiffs and unelected special prosecutors lack a democratic mandate to obstruct a President chosen by the American people; but Congress is elected to oversee the executive, and where necessary to enact reform laws. If Congress itself were to subpoena Cheney, he should not lightly disregard the people's representatives. (In 1974, the House Judiciary Committee voted to impeach Richard Nixon for defying certain congressional subpoenas.) The matter, however, is rather different if Congress continues to hide behind the politically unaccountable General Accounting Office rather than confront Cheney directly.
If the Bush Administration seeks to limit the damage already done to executive privilege, it should find a stronger case in which to assert it a case involving purely executive officers making an executive decision where there is no reason to think the government is trying to cover up any misconduct. Both the Nixon and Clinton Administrations pushed executive privilege on bad facts, and lost. Surely the Bush Administration can find a better place to make a last stand for privilege than Fort Enron.
Akhil Reed Amar teaches constitutional law at Yale and is the author of "The Bill of Rights: Creation and Reconstruction."