In preparing for my radio gig yesterday, I puzzled over an interesting question (about which I was not asked): Is the argument for judicial intervention in cases involving a claim of executive privilege weaker or stronger when Congress (or a committee thereof) asks for the allegedly privileged info or when it is sought in the course of ordinary litigation? The conventional wisdom says that where Congress seeks the info, the courts are less likely to get involved, because, per the theory of checks and balances, Congress and the President can fight it out in the political arena.
That conventional wisdom appears to draw support from U.S. v. Nixon, in which the Court emphasized rule-of-law values in saying that the President, like any other citizen, must comply with the regular orders of a criminal investigation--at least absent a specific showing that the President needs a shield. In Cheney v. U.S. District Court the Supreme Court did not technically adjudicate a claim of executive privilege, but it drew a fairly sharp distinction between criminal and civil proceedings. One could read Justice Kennedy's opinion there as construing Nixon as turning on the unique function of a criminal investigation. It also could not have been lost on the majority that although the plaintiffs in Cheney were NGOs, members of Congress were effectively lined up contrary to the President. On this reading, Nixon and Cheney support the conventional wisdom: a criminal trial uniquely calls for judicial override of executive privilege in a way that a dispute between the President and Congress does not.
Yet the cases hardly compel that result, and there is sound policy basis for thinking nearly the opposite. When the Court faces a claim of executive privilege in a case to which Congress is not a party, it must decide for itself how to balance the executive's asserted need for secrecy against the public interest. That balance is necessarily subjective, and one might wonder why the Court is better situated than the Executive to strike it. By contrast, if the Court overrides a claim of executive privilege at the behest of Congress, a politically accountable branch has made the necessary judgment. This argument wouldn't necessarily warrant rejection of all executive privilege claims in litigation against Congress, but it would imply that the showing required of the President in such cases is at least as stringent as in a case like Nixon. (I credit my colleague Philip Hamburger for inspiring this point, unless it's wrong, in which case I take the blame.)