Bush critics can't have it both ways... Executive privilege and Congressional subpoena power stem from the same source

Many of the same people claiming that the President has no "executive privilege," because it is not explicitly stated in the Constitution, blithely assume that Congress does indeed have the power to subpoena officials of the executive branch and compel their testimony before Congressional committees. David Schraub thinks so much of the one and so little of the other that he casually dismisses the very idea as patently ridiculous:

What is on the horizon is a court finally smacking down the President's argument that Congressional oversight is a separation of powers violation (Think I'm joking? Quoteth Tony Snow: "The executive branch is under no compulsion to testify to Congress, because Congress in fact doesn't have oversight ability."). There is no crisis, because there is really no question--outside Bush's fevered imagination, there is no doubt that Congress is a co-equal branch of government and indeed can hold executive branch agencies accountable.

Executive privilege, if it exists, is found only among the "inherent" powers of the President, powers which the Supreme Court has, over time, found so essential to the exercise of his Article II powers that they are deemed to be included simply by the nature of the thing. But the subpoena power rests on no less murky a foundation, and its footing may be even less certain than that, though certainly it has been upheld by the Supreme Court several times.

The word "subpoena" is found nowhere in the text of the Constitution. The word "compel" (as in "compel the attendance of...") is found only in Art. I, sec. 5, empowering Congress to compel the attendance of its members (the word is also in the 5th Amendment, not relevant here). Nowhere else. There is no clause which expressly grants Congress the authority to conduct "investigations" of any sort, whether into private conduct or conduct of executive branch officials, other than its impeachment power. The Congressional Research Service offers a history of Congressional investigative power.

Like executive privilege, the Supreme Court has, however, historically determined that the power to compel the attendance of witnesses is an inherent component of the legislative power. In the 1927 case of McGrain v. Daugherty, the Court upheld the enforcement of a Senate committee's subpoena to a witness, while the Senate was investigating the performance of the Attorney General. As a Senate committee, the only basis for the subpoena was general legislative power, not the impeachment power (since that remains in the House until sent to the Senate for trial), and the Court found that the allegations of misfeasance by the Attorney General provided a proper foundation on which the Senate might wish to base legislation. (The case is a bit scary, because it upholds the authority of the Senate Sergeant at Arms to bodily arrest someone who has ignored the order and personally bring them to the Senate, not merely seek enforcement of the subpoena through the judicial branch.)

Despite its assurances to the contrary, the McGrain decision seems to me quite contrary to the result in the 1880 case of Kilbourn v Thompson. In Kilbourn, the House of Representatives was investigating the "improvident deposit" by the Secretary of the Navy of large sums of federal government funds into the firm of Jay Cooke & Co., which subsequently filed for bankruptcy. As part of its investigation, it subpoenaed several individuals, who refused to testify on the grounds that Congress had no power to subpoena them. The Court agreed, finding that, because the matter was in the hands of the bankruptcy court, Congress was attempting to exercise the judicial, not the legislative, function.

A more recent, and quite alarming, case is the 1975 opinion by Chief Justice Burger in Eastland v. United States Servicemen's Fund. The USSF was under investigation by Congress as a possible subversive organization, funded by foreign enemies. The Senate Subcommittee on Internal Security issued a subpoena to the USSF's bank to obtain its records, which would have revealed the names of its members (generally protected by the First Amendment). The Court basically held that the Speech and Debate clause of the Constitution prohibited issuance of an injunction to protect the First Amendment rights of the USSF. Justice Marshall concurred in the judgment for other reasons, writing separately that he disagreed with the breadth of the majority's opinion and emphasizing that the Court could review and pass on the constitutionality of the Congressional subpoena had the bank refused to comply, and then been brought by the Senate to the courts for enforcement of the subpoena and contempt charges.

As always when these partisan brouhahas erupt, it is necessary to remind everybody that these conflicts between the President and Congress are primarily institutional, not partisan, though they arise more often when those institutions are occupied by different parties. The Clinton Justice Department opined that a Congressional subpoena issued while Congress was adjourned sine die, had no validity.

In conclusion, it seems fairly settled that Congress has the legal authority to subpoena the executive branch and private parties for whatever information it deems appropriate and necessary to conduct its legislative duties. However, that power stems only from the same source as the President's executive privilege... the inherent powers of the institution, not any positive granting by the text of the Constitution. As Tully is fond of noting, these "crises" are most often resolved by compromise, as neither side wishes to push the matter to an ultimate testing in court or elsewhere. The principles of comity between branches demands as much.